Information on EC 6.6.1.1 - magnesium chelatase

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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria

EC NUMBER
COMMENTARY
6.6.1.1
-
RECOMMENDED NAME
GeneOntology No.
magnesium chelatase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
subunits H, I and D from bchH, bchI and bchD genes combine to form the enzyme complex, the complex is active only when the three proteins are present
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
subunits H, I and D from bchH, bchI and bchD genes combine to form the enzyme complex, the complex is active only when the three proteins are present
O24133
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
subunits H, I and D from bchH, bchI and bchD genes combine to form the enzyme complex, the complex is active only when the three proteins are present
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
subunits H, I and D from bchH, bchI and bchD genes combine to form the enzyme complex, the complex is active only when the three proteins are present
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
subunits H, I and D from bchH, bchI and bchD genes combine to form the enzyme complex, the complex is active only when the three proteins are present
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
complex three-subunit enzyme
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
this is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway
-
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+
show the reaction diagram
linear reaction for at least 60 min under standard incubation
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Ligation
-
-
-
-
PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Biosynthesis of secondary metabolites
-
-
chlorophyll metabolism
-
-
chlorophyllide a biosynthesis I (aerobic, light-dependent)
-
-
chlorophyllide a biosynthesis II (anaerobic)
-
-
chlorophyllide a biosynthesis III (aerobic, light independent)
-
-
Metabolic pathways
-
-
Porphyrin and chlorophyll metabolism
-
-
SYSTEMATIC NAME
IUBMB Comments
Mg-protoporphyrin IX magnesium-lyase
This is the first committed step of chlorophyll biosynthesis and is a branchpoint of two major routes in the tetrapyrrole pathway.
SYNONYMS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ABAR
-
369 amino acid residues (631-999) of chelatase H subunit
ABAR/CHLH
-
putative abscisic acid receptor/chelatase H subunit
BchD
P26162
magnesium chelatase subunit
BchH
P26162
magnesium chelatase subunit
BchI
P26162
magnesium chelatase subunit
BchI
P26239
38 kDa subunit I, Mg-chelatase consists of three subunits BchH, BchD and BchI, subunits D and I form the AAA+ motor complex in the presence of ATP and Mg2+, whereas subunit H binds protoporphyrin IX
chelatase H subunit
-
-
ChlH
E2D957
magnesium chelatase H subunit
ChlH
-
subunit of the magnesium chelatase
ChlH
Synechocystis sp. PCC6803
-
subunit of the magnesium chelatase
-
ChlHID
Synechocystis sp. PCC6803
-
-
-
CHLI protein
-
-
H subunit of Mg-chelatase
-
-
magnesium chelatase
-
-
magnesium chelatase
Q94C01
-
magnesium chelatase
P26239
-
magnesium chelatase
-
-
magnesium-chelatase
-
-
-
-
magnesium-protoporphyrin chelatase
-
-
-
-
magnesium-protoporphyrin IX chelatase
-
-
-
-
magnesium-protoporphyrin IX chelatase
-
-
Mg chelatase
-
-
Mg chelatase
-
-
Mg chelatase
-
-
Mg-chelatase
-
-
-
-
Mg-chelatase
-
consists of three subunits interactions BchH or ChlH, BchD or ChlD, and BchI or ChlI
Mg-chelatase
P26239
-
Mg-chelatase
-
-
Mg-chelatase
Synechocystis sp. PCC6803
-
-
-
Mg-chelatase H
-
subunit
Mg-protoporphyrin IX magnesio-lyase
-
-
-
-
Oil Yellow1
Q4FE78
Oil yellow1 (Oy1) gene encodes the I subunit of magnesium chelatase
Oy1
Q4FE78
Oil yellow1 (Oy1) gene encodes the I subunit of magnesium chelatase
protoporphyrin IX magnesium-chelatase
-
-
-
-
protoporphyrin IX Mg-chelatase
-
-
-
-
XanF
Q94C01
subunit H
Xantha-f
Q94C01
gene name of subunit H
ZmChlI
Q4FE78
-
CAS REGISTRY NUMBER
COMMENTARY
9074-88-8
-
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
ecotype Col-0
-
-
Manually annotated by BRENDA team
ecotype Columbia
-
-
Manually annotated by BRENDA team
subunit isoforms ChlI1 and ChlI2
-
-
Manually annotated by BRENDA team
in wild-type cells, a shift from dark to light results in a transient reduction in heme levels, while the levels of Mg-protoporphyrin IX, its methyl ester, and protoporphyrin IX increase. Hemin feeding to cultures in the dark activates HSP70A
Uniprot
Manually annotated by BRENDA team
isoform BchH1
UniProt
Manually annotated by BRENDA team
isoform BchH2
UniProt
Manually annotated by BRENDA team
isoform BchH3
UniProt
Manually annotated by BRENDA team
cucumber, var Beit Alpha
-
-
Manually annotated by BRENDA team
Sumter var
-
-
Manually annotated by BRENDA team
soybean
-
-
Manually annotated by BRENDA team
soybean; var Resnik
-
-
Manually annotated by BRENDA team
barley
-
-
Manually annotated by BRENDA team
cultivar 'Svalfs Bonus'
TREMBL
Manually annotated by BRENDA team
tobacco
Uniprot
Manually annotated by BRENDA team
tobacco; var Samsun NN
-
-
Manually annotated by BRENDA team
pea; var Bolero; var Spring
-
-
Manually annotated by BRENDA team
cultivar Hongdeng
UniProt
Manually annotated by BRENDA team
; BchH-deficient strain ZY6; SG1001 strain
UniProt
Manually annotated by BRENDA team
magnesium chelatase subunit H
UniProt
Manually annotated by BRENDA team
Rhodobacter capsulatus SG1001
SG1001 strain
UniProt
Manually annotated by BRENDA team
Synechocystis sp. PCC6803
-
-
-
Manually annotated by BRENDA team
Synechocystis sp. PCC6803
PCC6803
-
-
Manually annotated by BRENDA team
magnesium chelatase subunit I precursor
SwissProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
malfunction
-
CHLH RNAi-silenced plants show phenotypes in which stomatal movements are insensitive to abscisic acid
malfunction
-
mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light
malfunction
-
a rtl1 mutant allele of the CHLH gene in Arabidopsis thaliana shows ABA-insensitive phenotypes in both stomatal movement and seed germination, overexpression of CHLD gene shows wild-type ABA sensitivity in Arabidopsis
metabolism
P26239
Mg-chelatase catalyzes the first step of the chlorophyll biosynthetic pathway
metabolism
-
magnesium chelatase catalyses the first committed step of chlorophyll biosynthesis
metabolism
Synechocystis sp. PCC6803
-
magnesium chelatase catalyses the first committed step of chlorophyll biosynthesis
-
physiological function
-
Mg-chelatase H subunit affects abscisic acid signaling in stomatal guard cells, but is not an abscisic acid receptor
physiological function
-
the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR) functions as a receptor for abscisic acid in Arabidopsis thaliana. ABAR is a key component connecting the circadian clock with abscisic acid-mediated plant responses to drought. ABAR antagonizes negative abscisic acid signaling regulators WRKYs to derepress abscisic acid-responsive genes
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
ATP + deuteroporphyrin + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin + H+
show the reaction diagram
-
-
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
-
-
-
-
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
Q94C01
-
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
magnesium chelatase catalyzes the first committed step in chlorophyll biosynthesis
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
ATP utilization by magnesium chelatase is solely connected to the I-subunit
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
MgATP2- binding occurs after the rate-determining step, nucleotide binding acts to clamp the chelatase in a product complex
-
-
?
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
Synechocystis sp. PCC6803
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
O22437
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
O24133
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
P26162
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
P51634
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
Q8KB39, Q93SV6, Q93SV9
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
P26162
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
E2D957
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
omission of any of the substrates results in complete loss of activity. Optimum concentration of Mg2+ is lower for intact than broken and reconstituted chloroplasts
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
optimum activity at 11.5 mM Mg2+
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
magnesium chelatase H subunit markedly enhances magnesium protoporphyrin methyltransferase catalysis by accelerating the formation and breakdown of the catalytic intermediate, providing a kinetic link between the first two reactions of chlorophyll biosynthesis with the signalling molecule magnesium protoporphyrin as the common factor
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
the enzyme catalyzes the insertion of magnesium into protoporphyrin IX, the first unique step of the chlorophyll biosynthetic pathway
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
insertion of magnesium into protoporphyrin IX by magnesium chelatase is a key step in the chlorophyll biosynthetic pathway
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
Mg chelatase is a multi-subunit enzyme that catalyses the first committed step of chlorophyll biosynthesis. The Mg chelatase reaction product, Mg-protoporphyrin IX plays an essential role in nuclear-plastid interactions
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
Synechocystis sp. PCC6803
-
magnesium chelatase H subunit markedly enhances magnesium protoporphyrin methyltransferase catalysis by accelerating the formation and breakdown of the catalytic intermediate, providing a kinetic link between the first two reactions of chlorophyll biosynthesis with the signalling molecule magnesium protoporphyrin as the common factor
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
Synechocystis sp. PCC6803
-
-
-
-
?
additional information
?
-
P26162
BchH is the rate-limiting component of Mg chelatase in cell extracts, and its slective inactivation during adaption to aerobic growth may account for the rapid inactivation of Mg chelatase in vivo when anaerobically growing cells are exposed to O2 in the light
-
-
-
additional information
?
-
-
the pattern of changes in RNA transcript levels of the magnesium chelatase genes, chlH, chlD and chlI of Chlamydomonas reinhardtii grown under synchronous culture conditions in light/dark cycles are similar. Light is involved in regulation
-
-
-
additional information
?
-
-
mutant with a non-functional magnesium chelatase subunit D assembles a Zn-BChl photosystem
-
-
-
additional information
?
-
-
subunit isoform ChlI2 shows ATPase activity, but with lower Vmax and higher Km value than isoform ChlI1. Although it plays a limited role in chlorophyll biosynthesis, it certainly contributes to the assembly of the Mg-chelatase complex
-
-
-
additional information
?
-
-
enzyme is composed of subunits BchI, BchD, BchH. The BchIBchD complex has intrinsic ATPase activity, and addition of BchH greatly increased ATPase activity. This is concentration-dependent and gives sigmoidal kinetics. ATPase activity is about 40fold higher than magnesium chelatase activity and continues despite cessation of magnesium chelation, implying secondary roles for ATP hydrolysis. Porphyrin binding is the rate limiting step in catalysis
-
-
-
additional information
?
-
-
ABAR interacts with the transcription factors WRKY40, WRKY18, and WRKY60
-
-
-
additional information
?
-
P26162
BchJ may serve as an Mg-protoporphyrin carrier between the BchH Mg-protoporphyrin and BchM
-
-
-
additional information
?
-
-
CHLH does not bind abscisic acid
-
-
-
additional information
?
-
-
using a surface plasmon resonance system, it is shown that abscisic acid binds to CHLH, but not to the other Mg-chelatase components/subunits CHLI, CHLD (D subunit) and GUN4
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
ATP + deuteroporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-deuteroporphyrin IX + H+
show the reaction diagram
-
magnesium chelatase catalyzes the first committed step in chlorophyll biosynthesis
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
O22437
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
O24133
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
P26162
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
P51634
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
magnesium chelatase H subunit markedly enhances magnesium protoporphyrin methyltransferase catalysis by accelerating the formation and breakdown of the catalytic intermediate, providing a kinetic link between the first two reactions of chlorophyll biosynthesis with the signalling molecule magnesium protoporphyrin as the common factor
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
the enzyme catalyzes the insertion of magnesium into protoporphyrin IX, the first unique step of the chlorophyll biosynthetic pathway
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
-
insertion of magnesium into protoporphyrin IX by magnesium chelatase is a key step in the chlorophyll biosynthetic pathway
-
-
?
ATP + protoporphyrin IX + Mg2+ + H2O
ADP + phosphate + Mg-protoporphyrin IX + H+
show the reaction diagram
Synechocystis sp. PCC6803
-
magnesium chelatase H subunit markedly enhances magnesium protoporphyrin methyltransferase catalysis by accelerating the formation and breakdown of the catalytic intermediate, providing a kinetic link between the first two reactions of chlorophyll biosynthesis with the signalling molecule magnesium protoporphyrin as the common factor
-
-
?
additional information
?
-
P26162
BchH is the rate-limiting component of Mg chelatase in cell extracts, and its slective inactivation during adaption to aerobic growth may account for the rapid inactivation of Mg chelatase in vivo when anaerobically growing cells are exposed to O2 in the light
-
-
-
additional information
?
-
-
the pattern of changes in RNA transcript levels of the magnesium chelatase genes, chlH, chlD and chlI of Chlamydomonas reinhardtii grown under synchronous culture conditions in light/dark cycles are similar. Light is involved in regulation
-
-
-
additional information
?
-
-
mutant with a non-functional magnesium chelatase subunit D assembles a Zn-BChl photosystem
-
-
-
additional information
?
-
-
subunit isoform ChlI2 shows ATPase activity, but with lower Vmax and higher Km value than isoform ChlI1. Although it plays a limited role in chlorophyll biosynthesis, it certainly contributes to the assembly of the Mg-chelatase complex
-
-
-
additional information
?
-
-
using a surface plasmon resonance system, it is shown that abscisic acid binds to CHLH, but not to the other Mg-chelatase components/subunits CHLI, CHLD (D subunit) and GUN4
-
-
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Mg2+
-
required
Mg2+
-
the magnesium-rich form of the chelatase is a more effective catalyst of the chelation reaction. Magnesium activation of the chelatase increases V, as well as the specificity constant for the reaction of MgATP2-
Mg2+
Q8KB39, Q93SV6, Q93SV9
K0.5 value 8.6 mM; K0.5 value 9.1 mM; K0.5 value 9.1 mM
Mg2+
P26162
required
Mg2+
-
required
Mg2+
E2D957
required
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
Mg2+
-
marked inhibition above 10 mM
N-ethylmaleimide
-
potent, IC50 of 0.02 mM
N-ethylmaleimide
-
binds to ChlI subunit and inhibits its ATPase activity. The ChlI-ChlD-ATP complex forms but cannot catalyse magnesium chelation. Prior incubation with MgATP2- affords protection. Full protection can also be obtained with 5 mM ATP or 5 mM ADP alone
porphyrin
-
at high ChlH concentrations, substrate inhibition is very noticeable
thiomerosal
-
60% inhibition with 0.022 mM, in the absence of DTT
thioredoxin
-
ATPase activity of recombinant CHLI1 is fully inactivated by oxidation and easily recovered by thioredoxin-assisted reduction
Urea
-
20% inhibition with 100 mM, 50% inhibition with 250 mM, 90% inhibition with 800 mM
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
5-aminolevulinic acid
-
0.01 mM, increases activity
ATP
-
required for activation and chelation steps
GENOMES UNCOUPLED 4
-
GUN4 enhances measureable Mg-protoporphyrin IX in chloroplast extracts
-
Gun4
-
addition of Gun4 up to 0.0005 mM stimulates the wild type enzyme 2-3fold. Up to 0.001 mM Gun4 resurrects the inactive gun5 and cch mutant Mg-chelatase reactions to the level seen in the wild type with no Gun4 present, particularly in the case of mutant gun5
-
GUN4 protein
-
activates Mg-chelatase
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.026
ATP
-
pH 8.5, 32C
0.091
ATP
-
30C, apparent Km value
0.45
ATP
-
-
0.8
ATP
-
pH 7.7, 45C
0.00099
deuteroporphyrin
-
mutant R289A, pH 7.7, 34C
0.0012
deuteroporphyrin
-
mutant E152Q, pH 7.7, 34C
0.0057
deuteroporphyrin
-
pH 7.7, 37C, 100 nM ChlH subunit
0.0057
deuteroporphyrin
-
wild-type, pH 7.7, 34C
0.00631
deuteroporphyrin
-
mutant R208A, pH 7.7, 34C
0.008
deuteroporphyrin
-
pH 7.7, 37C, 200 nM ChlH subunit
0.0032
deuteroporphyrin IX
-
-
1.3
Mg2+
-
30C, apparent Km value
2.3
Mg2+
-
pH 7.7, 45C
0.0006
protoporphyrin IX
Q8KB39, Q93SV6, Q93SV9
complex of subunits BchD, BchI, BchH2, pH 8.0, 34C
0.00089
protoporphyrin IX
-
pH 8.2, 20-22C, 192000 * g supernatant
0.0012
protoporphyrin IX
Q8KB39, Q93SV6, Q93SV9
complex of subunits BchD, BchI, BchH-1, pH 8.0, 34C; complex of subunits BchD, BchI, BchH1, pH 8.0, 34C
0.00123
protoporphyrin IX
-
pH 8.0, 30C
0.00283
protoporphyrin IX
-
pH 8.2, 20-22C, 20000 * g supernatant
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.0009
ATP
-
mutant R289A, pH 7.7, 34C
0.0018
ATP
-
mutant E152Q, pH 7.7, 34C
0.0043
ATP
-
mutant R208A, pH 7.7, 34C
0.0061
ATP
-
pH 7.7, 45C
0.0067
ATP
-
wild-type, pH 7.7, 34C
0.0013
deuteroporphyrin
-
mutant R289A, pH 7.7, 34C
0.003
deuteroporphyrin
-
mutant E152Q, pH 7.7, 34C
0.014
deuteroporphyrin
-
mutant R208A, pH 7.7, 34C
0.0188
deuteroporphyrin
-
wild-type, pH 7.7, 34C
0.013
deuteroporphyrin IX
-
-
0.0028
Mg2+
-
mutant E152Q, pH 7.7, 34C
0.0065
Mg2+
-
pH 7.7, 45C
0.0081
Mg2+
-
wild-type, pH 7.7, 34C
0.0083
Mg2+
-
mutant R208A, pH 7.7, 34C
0.0003
protoporphyrin IX
Q8KB39, Q93SV6, Q93SV9
complex of subunits BchD, BchI, BchH1, pH 8.0, 34C; complex of subunits BchD, BchI, BchH3, pH 8.0, 34C
0.03
protoporphyrin IX
Q8KB39, Q93SV6, Q93SV9
complex of subunits BchD, BchI, BchH2, pH 8.0, 34C
kcat/KM VALUE [1/mMs-1]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.0075
ATP
-
pH 7.7, 45C
4
0.0028
Mg2+
-
pH 7.7, 45C
6
Ki VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.005
porphyrin
-
pH 7.7, 45C. At high ChlH concentrations, substrate inhibition is very noticeable
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.02
N-ethylmaleimide
-
potent, IC50 of 0.02 mM
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
0.000002
-
activity in chloroplast extracts
0.0000024
-
pellet of broken fractionated chloroplasts
0.0000026
-
supernatant of broken fractionated chloroplasts
0.00002
-
broken unfractionated chloroplasts
0.0001
-
intact chloroplasts
additional information
-
3fold to 4fold higher values than in cucumber chloroplasts
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
7.7
-
assay at
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
28
-
assay at
30
P26162
assay at
32
-
assay at
34
-
assay at
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
-
generation of transgenic tobacco lines with RNAi silenced expression of the glutamate 1-semialdehyde aminotransferase (GSA) gene does not cause a decrease in the transcript levels after inactivation of HEMA and GSA-expression. Enzyme activity for Mg chelatase is lower in parallel to the loss of chlorophyll and heme content
Manually annotated by BRENDA team
-
the CHLH gene encoding the H subunit of Mg-chelatase is induced by continuous white, red, far-red or blue light with an initial peak after 24 h light. Mg-chelatase subunit genes CHLI and CHLD and the ferrochelatase genes FC1 and FC2 are not strongly regulated at the level of transcript abundance, but the Mg-chelatase regulator GUN4 has an expression profile almost identical to that observed for CHLH. Transcription of both CHLH and GUN4 is primarily under the control of phytochromes A and B and compromised in the phytochrome-signalling mutants fhy1 and fhy3
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
-
ABAR spans the chloroplast envelope with its N- and C-termini exposed to cytosol
Manually annotated by BRENDA team
additional information
-
multicomponent enzyme, requires at least two proteins, one membrane-associated and one soluble
-
Manually annotated by BRENDA team
PDB
SCOP
CATH
ORGANISM
Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)
Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
43000
-
subunit I ChlI, SDS-PAGE
709047
44000
-
subunit I ChlI, SDS-PAGE
709047
93000
-
subunit D ChlD, SDS-PAGE
709047
94000
-
subunit D ChlD, SDS-PAGE
709047
148000
-
-
727938
150000
-
subunit H ChlH, SDS-PAGE
709047
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
-
x * 44000, SDS-PAGE, ChlI subunit
?
-
x * 153491, calculation from sequence of cDNA, ChlH subunit
?
-
x * 38000, SDS-PAGE, a construct expressing I subunit, x * 42000, SDS-PAGE, a construct expressing I subunit
?
O24133
x * 82900, calculation from sequence of cDNA, D subunit
?
-
x * 73000, calculation from sequence of cDNA, D subunit
?
-
x * 90000-130000, gel filtration, BchI subunit
?
-
x * 46000, calculation from sequence of cDNA, I subunit
?
-
x * 46000, calculation from sequence of cDNA, I subunit
?
-
x * 87000, calculation from sequence of cDNA, D subunit
?
P51634
x * 60000, calculation from sequence of cDNA, D subunit
?
-
x * 40000, SDS-PAGE, I subunit
?
-
x * 40000 + x * 70000 + x * 140000
dimer
-
2 * 40000, BchI subunit
heterotrimer
-
1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD
octamer
-
8 * 70000, D subunit, the molecular mass of the polymeric protein is approximately 550000 Da
trimer
-
1 * 40000 (I-subunit) + 1 * 70000 (D-subunit) + 1 * 140000 (H-subunit)
heterotrimer
Synechocystis sp. PCC6803
-
1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD
-
additional information
P51634
-
additional information
-
1 * 148000, gel filtration, ChlH subunit
additional information
-
1 * 110000, gel filtration, BchH subunit
additional information
-
1 * 140000, BchH subunit
additional information
-
the enzyme has three subunits, BchI, BchH and BchD
additional information
-
the enzyme has three subunits, BchI, BchH and BchD
additional information
-
the enzyme has three subunits, BchI, BchH and BchD
additional information
-
M1 and M2 domains of ChlD subunit participate in homodimerization and interaction between ChlI and ChlD
additional information
-
ChlI subunit forms high-molecular-mass aggregates
additional information
-
I subunit is hexameric
additional information
-
ChlH forms high-molecular aggregates when preincubated with ATP and Mg2+
additional information
-
H subunit is a monomer and I subunit is a dimer, determined by dynamic-light-scattering studies
additional information
-
the enzyme has three subunits, ChlI, ChlH and ChlD
additional information
O24133
the enzyme has three subunits, ChlI, ChlH and ChlD
additional information
-
the enzyme has three subunits, ChlI, ChlH and ChlD
additional information
-
the 40000 Da subunit functions as a chaperon that is esential for the survival of the 70000 Da subunit. The ATPase activity of the 40000 Da subunit is essential for this function. Binding between the two subunits is not sufficient to maintain the 70000 Da subunit in the cell
additional information
Q8KB39, Q93SV6, Q93SV9
enzyme interacts with the next enzyme in the pathway, magnesium protoporphyrine IX methyltransferase BchM. Activitiy of BchM in presence of isoform BchH1 is 132% of the activity of BchM alone
additional information
Q8KB39, Q93SV6, Q93SV9
enzyme interacts with the next enzyme in the pathway, magnesium protoporphyrine IX methyltransferase BchM. Activitiy of BchM in presence of isoform BchH2 is 157% of the activity of BchM alone
additional information
Q8KB39, Q93SV6, Q93SV9
enzyme interacts with the next enzyme in the pathway, magnesium protoporphyrine IX methyltransferase BchM. Activitiy of BchM in presence of isoform BchH3 is 68% of the activity of BchM alone
additional information
-
enzyme is composed of subunits BchI, BchD, BchH. The BchIBchD complex has intrinsic ATPase activity, and addition of BchH greatly increased ATPase activity. This is concentration-dependent and gives sigmoidal kinetics. ATPase activity is about 40fold higher than magnesium chelatase activity and continues despite cessation of magnesium chelation, implying secondary roles for ATP hydrolysis
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
multiple wavelength anomalous dispersion method
-
subunit BchH, at 25 A resolution. The apo structure contains three major lobe-shaped domains connected at a single point with additional densities at the tip of two lobes termed the thumb and finger. The substrate-bound BchH complex BchH Proto shows a distinct conformational change in the thumb and finger subdomains. Prolonged proteolysis of native apo-BchH produces a stable C-terminal fragment of 45 kDa, and protoporphyrin protects the full-length polypeptide from degradation
-
using electron microscopy and small-angle x-ray scattering the structure of ChlH subunit is investigated. ChlH is a large, 148-kDa protein of 1326 residues, forming a cage-like assembly comprising the majority of the structure, attached to a globular N-terminal domain of 16 kDa by a narrow linker region. This N-terminal domain is adjacent to a 5 nm-diameter opening in the structure that allows access to a cavity
-
pH STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
-
inactive below pH 6.0 and above pH 10.5
644267
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
55
-
melting temperature
726914
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
high concentrations of protoporphyrin, ATP and Mg2+ during gentle lysis, stabilise
-
26% loss of activity in chloroplasts subjected to hypotonic lysis and freeze-thaw cycles
-
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Ni-NTA agarose column chromatography and glutathione Sepharose 4B bead chromatography
-
recombinant enzyme
-
cation exchange chromatography
-
HisTrap Ni2+ crude FF chelating column chromatography, gel filtration
P26162
using Ni-NTA chromatography
-
mutant enzymes are purified by Ni2+ affinity column chromatography
-
using Ni-NTA chromatography
-
using Ni-NTA chromatography
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed in Escherichia coli and Arabidopsis thaliana Col-0 after transformation with Agrobacterium tumefaciens
-
expressed in Escherichia coli BL21 cells
-
expression in Escherichia coli
-
expression in Escherichia coli; expression in Escherichia coli; expression in Escherichia coli
Q8KB39, Q93SV6, Q93SV9
cloning and sequencing of xantha-f mutants (140000 Da subunit)
-
expression of central CHLD region in yeast
-
expression in Escherichia coli
O22437
expression in Escherichia coli
-
BchD, BchI and BchH proteins are expressed in Escherichia coli from the respective cloned Rhodobacter capsulatus genes; expression of bchD gene in Escherichia coli
P26162
expressed in Escherichia coli
P26239
expressed in Escherichia coli as a His-tagged fusion protein
-
expression in Escherichia coli
-
expression of bchD gene in Escherichia coli
-
Rhodobacter capsulatus H-subunit produced in Escherichia coli
-
expression in Escherichia coli
-
expression of bchD gene in Escherichia coli
-
expressed in Escherichia coli as a His-tagged fusion protein
-
expression in Escherichia coli
-
mutant enzymes are expressed in Escherichia coli
-
expressed in Escherichia coli as a His-tagged fusion protein
-
expression of mutant maize ChlI alleles in Nicotiana benthamiana results in the formation of chlorotic lesions within 4 d of inoculation. Transient expression provides a convenient, high-throughput, qualitative assay for functional variation in the CHLI protein
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
down-regulation of CHLI confers abscisic acid insensitivity in stomatal response in Arabidopsis
-
up-regulation of CHLI1 results in abscisic acid hypersensitivity in seed germination
-
CHLH1 expression dramatically declines after 25 days after full bloom. The application of abscisic acid significantly decreases the expression of CHLH1 in fruits
E2D957
the relative expression of CHLH1 in dehydrated leaves is 1.3times higher than that in control leaves
E2D957
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
L348F
-
named abar-2, altered abscisic acid-related phenotypes in seed germination and postgermination growth but not in stomatal movement
D207N
-
altered restriction enzyme site, no measurable magnesium chelatase activity, ATPase activity not affected
E424
Q94C01
deletion mutant (3bp) named xantha-f.10, no magnesium chelatase activity
L111F
-
altered restriction enzyme site, no measurable magnesium chelatase activity, ATPase activity not affected
M632R
Q94C01
missense mutation named xantha-f.26, leaky mutant with 8% to 10% of the chlorophyll content but 100% protein level of wild-type phenotype
R298K
-
altered restriction enzyme site, no measurable magnesium chelatase activity, ATPase activity not affected
D207N
-
BchI mutant forms a complex with wild-type BchD. Mutant shows 7.2% of wild-type ATPase activity. Mutant is deficient of magnesium chelatase activity
R289K
-
BchI mutant forms a complex with wild-type BchD. Mutant shows 10.9% of wild-type ATPase activity. Mutant is deficient of magnesium chelatase activity
A942V
-
the (gun5) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM restores approximately 50% activity in the presence of the gun5 mutation. The addition of Gun4 restores Mg-chelatase activity of the gun5 mutant enzyme
E152Q
-
mutation in the AAA+ domain of ChlD binds to ChlI. Mutant shows low activity but assembles into complexes much like wild-type. Mutant shows 25% of wild-type activity. kcat/K0.5 for Mg2+ is 30% of wild-type. kcat and Km for deuteroporphyrin are reduced to the same extent
P595L
-
the (cch) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM fully restores activity in the presence of the cch mutation. The addition of Gun4 restores Mg-chelatase activity of the cch mutant enzyme
R208A
-
mutation in the AAA+ domain of ChlD binds to ChlI. Mutant shows reduced binding affinity to ChlI.Mutant shows 50% of wild-type activity (least impaired mutant). Effect on substrate handling is modest compared to wild-type. Specifictiy constants for Mg2+ and porphyrin are 70% of wild-type
R289A
-
mutation in the AAA+ domain of ChlD binds to ChlI. Mutant shows reduced binding affinity to ChlI. Mutant shows 13% of wild-type activity. Mutant does not show a cooperative response to MgATP2- and has much weaker specificity toward Mg2+ than wild-type. Mutant has a lower specificity toward free porphyrin than wild-type
A942V
Synechocystis sp. PCC6803
-
the (gun5) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM restores approximately 50% activity in the presence of the gun5 mutation. The addition of Gun4 restores Mg-chelatase activity of the gun5 mutant enzyme
-
L690F
-
missense mutation of CHLH responsible for the rtl1 phenotype with abscisic acid-insensitive stomatal movements
additional information
-
in a chli2 T-DNA knockout line the visible phenotype of homozygous mutants is almost comparable to wild type, but the mutant accumulates significantly less chlorophyll. Isoform ChlI1/Chli2 double mutants cs/cs; chli2/chli2 are almost albino
S183F
-
named abar-3, altered abscisic acid-related phenotypes in seed germination and postgermination growth but not in stomatal movement
additional information
Q94FT3
isolation of mutants defective in subunits ChlH and ChlD. Mutants lack chlorophyll and show reduced levels of Mg-tetrapyrroles but increased levels of soluble heme. In the mutants, light induction of HSP70A is preserved, although Mg-protoporphyrin IX has been implicated in this induction
additional information
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gene silencing by use of silencing vector from the geminivirus Cotton leaf crumple virus (CLCrV), via replacement of the CLCrV coat protein gene by up to 500 bp of DNA homologous to the magnesium chelatase subunit I gene ChlI. Cotyledons of cotton cultivar Deltapine 5415 bombarded with the modified viral vectors manifest chlorosis in approximately 70% of inoculated plants after 2 to 3 weeks. Replication of viral DNA is restricted to vascular tissue and the viral vector can transmit to leaves, roots, and the ovule integument from which fibers originate. Plants grown at a 30C/26C day/night cycle have a greater than 10fold reduction in viral DNA accumulation compared to plants grown at 22C/18C
L111F
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BchI mutant forms a complex with wild-type BchD. Mutant shows 5.5% of wild-type ATPase activity. Mutant is deficient of magnesium chelatase activity
additional information
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mixing experiments with modified and wild-type BchI in various combinations show that an exchange of BchI subunits in magnesium chelatase occurs during the catalytic cycle, indicating that a dissociation of the complex may be part of the reaction mechanism
V113G
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BchI mutant forms a complex with wild-type BchD. Mutant shows 25% of wild-type ATPase activity. Mutant shows magnesium chelatase activity. Magnesium chelatase assays containing a mixture of mutant BchI V113G and wild-type BchI have the effect of stimulating the activity
additional information
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a bchD Mg-chelatase mutant of Rhodobacter sphaeroides produces an alternative bacteriochlorophyll a in which Mg2+ is substituted by Zn2+
K49A
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mutation in the AAA+ domain of ChlD binds to ChlI. Mutant shows no activity. Mutant forms detecable amount of ChlID complexes
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Synechocystis chelatase tolerates substitution of individual subunits with their Thermosynechococcus equivalents to produce hybrid enzymes.The heterologous complex is much less active than either of the two parent enzymes
P595L
Synechocystis sp. PCC6803
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the (cch) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM fully restores activity in the presence of the cch mutation. The addition of Gun4 restores Mg-chelatase activity of the cch mutant enzyme
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additional information
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Synechocystis chelatase tolerates substitution of individual subunits with their Thermosynechococcus equivalents to produce hybrid enzymes.The heterologous complex is much less active than either of the two parent enzymes
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
agriculture
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use of the CLCrV silencing vector to study gene function in cotton, via replacement of the CLCrV coat protein gene by up to 500 bp of DNA homologous to the magnesium chelatase subunit I gene ChlI. Temperature can have a major impact on the extent of geminivirus-induced gene silencing