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Information on EC 4.6.1.23 - ribotoxin and Organism(s) Aspergillus restrictus and UniProt Accession P67876

for references in articles please use BRENDA:EC4.6.1.23
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EC Tree
     4 Lyases
         4.6 Phosphorus-oxygen lyases
             4.6.1 Phosphorus-oxygen lyases (only sub-subclass identified to date)
                4.6.1.23 ribotoxin
IUBMB Comments
Ribotoxins are rRNA endonucleases that catalyse the cleavage of the phosphodiester bond between guanosine and adenosine residues at one specific position in 28S rRNA. The enzyme secreted by Aspergillus giganteus specifically cleaves rat 28S rRNA between G4325 and A4326 and displays cytotoxic activity toward animal cells. It can also act on bacterial rRNAs. The enzyme catalyses a two-stage endonucleolytic cleavage. The first reaction produces 5'-hydroxy-phosphooligonucletides and 3'-phosphooligonucleotides ending with 2',3'-cyclic phosphodiester, which are released from the enzyme. The enzyme then hydrolyses these cyclic compounds in a second reaction that takes place only when all the susceptible 3',5'-phosphodiester bonds have been cyclised. The second reaction is a reversal of the first reaction using the hydroxyl group of water instead of the 5'-hydroxyl group of ribose. The overall process is that of a phosphorus-oxygen lyase followed by hydrolysis to form the 3'-nucleotides.
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This record set is specific for:
Aspergillus restrictus
UNIPROT: P67876
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Word Map
The taxonomic range for the selected organisms is: Aspergillus restrictus
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria
Reaction Schemes
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a 28S rRNA containing guanosine-adenosine pair
+
=
an [RNA fragment]-3'-adenosine-3'-phosphate
+
a 5'-hydroxy-guanosine-3'-[RNA fragment]
Synonyms
alpha-sarcin, restrictocin, ribotoxin, mitogillin, ageritin, ribonuclease alpha-sarcin, rrna endonuclease, alpha-sarcin-like ribotoxin restrictocin, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
alpha-sarcin
-
-
-
-
alpha-sarcin-like ribotoxin restrictocin
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-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hydrolysis
-
-
-
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endoribonuclease reaction
-
-
-
-
SYSTEMATIC NAME
IUBMB Comments
[28S-rRNA]-guanosine-adenosine 5'-hydroxy-guanosine-ribonucleotide-3'-[RNA fragment]-lyase (cyclicizing; [RNA fragment]-3'-adenosine-2',3'-cyclophosphate-forming and hydrolysing)
Ribotoxins are rRNA endonucleases that catalyse the cleavage of the phosphodiester bond between guanosine and adenosine residues at one specific position in 28S rRNA. The enzyme secreted by Aspergillus giganteus specifically cleaves rat 28S rRNA between G4325 and A4326 and displays cytotoxic activity toward animal cells. It can also act on bacterial rRNAs. The enzyme catalyses a two-stage endonucleolytic cleavage. The first reaction produces 5'-hydroxy-phosphooligonucletides and 3'-phosphooligonucleotides ending with 2',3'-cyclic phosphodiester, which are released from the enzyme. The enzyme then hydrolyses these cyclic compounds in a second reaction that takes place only when all the susceptible 3',5'-phosphodiester bonds have been cyclised. The second reaction is a reversal of the first reaction using the hydroxyl group of water instead of the 5'-hydroxyl group of ribose. The overall process is that of a phosphorus-oxygen lyase followed by hydrolysis to form the 3'-nucleotides.
CAS REGISTRY NUMBER
COMMENTARY hide
1407-48-3
-
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
SRL + H2O
?
show the reaction diagram
-
sarcin/ricin loop in ribosomal RNA
-
-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.076
SRL
-
sarcin/ricin loop in ribosomal RNA, 10 mM Tris-HCl, 0-5 mM KCl, pH 7-7.4, 37°C
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
RNMG_ASPRE
176
0
19595
Swiss-Prot
-
CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
to 2.1 A resolution. The tertiary structure of the substrate RNA is important in protein-RNA recognition, fitting closely into the concavity of the presumed binding site
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
K63D
-
mutant with decreased activity for sarcin/ricin loop-cleavage of ribosomes
R21D/K28D
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mutant with decreased activity for sarcin/ricin loop-cleavage of ribosomes
R21D/K28D/K63D
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mutant with decreased activity for sarcin/ricin loop-cleavage of ribosomes
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
C-25 SP ion-exchange column, pH 5.5, 4°C
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
mutants K63D, R21D/K28D and R21D/K28D/K63D
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REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Korennykh, A.V.; Piccirilli, J.A.; Correll, C.C.
The electrostatic character of the ribosomal surface enables extraordinarily rapid target location by ribotoxins
Nat. Struct. Mol. Biol.
13
436-443
2006
Aspergillus restrictus
Manually annotated by BRENDA team
Yang, X.; Moffat, K.
Insights into specificity of cleavage and mechanism of cell entry from the crystal structure of the highly specific Aspergillus ribotoxin, restrictocin
Structure
4
837-852
1996
Aspergillus restrictus (P67876), Aspergillus restrictus
Manually annotated by BRENDA team