1.7.2.1: nitrite reductase (NO-forming)
This is an abbreviated version!
For detailed information about nitrite reductase (NO-forming), go to the full flat file.
Word Map on EC 1.7.2.1
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1.7.2.1
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anemia
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mellitus
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glycated
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hematocrit
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erythrocyte
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hematological
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women
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arterial
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glycemic
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transfusion
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platelet
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children
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albumin
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cardiovascular
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cholesterol
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postoperative
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ferritin
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fetal
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sickle
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creatinine
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preoperative
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bleeding
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cardiac
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erythropoietin
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hypertension
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heme
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triglyceride
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hemorrhage
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admission
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systolic
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venous
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demographic
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january
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hemolysis
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c-reactive
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erythroid
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hypoglycemia
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comorbidities
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reticulocyte
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hemodialysis
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transferrin
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admitted
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hemodynamic
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placebo
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diastolic
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intraoperative
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outpatient
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anthropometric
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bilirubin
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waist
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medicine
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analysis
- 1.7.2.1
- anemia
- mellitus
-
glycated
-
hematocrit
- erythrocyte
- hematological
- women
- arterial
-
glycemic
- transfusion
- platelet
- children
- albumin
- cardiovascular
- cholesterol
-
postoperative
- ferritin
- fetal
-
sickle
- creatinine
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preoperative
- bleeding
- cardiac
- erythropoietin
- hypertension
- heme
- triglyceride
- hemorrhage
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admission
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systolic
- venous
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demographic
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january
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hemolysis
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c-reactive
-
erythroid
- hypoglycemia
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comorbidities
- reticulocyte
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hemodialysis
- transferrin
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admitted
-
hemodynamic
-
placebo
-
diastolic
-
intraoperative
-
outpatient
-
anthropometric
- bilirubin
- waist
- medicine
- analysis
Reaction
Synonyms
AcNIR, AfNiR, AniA, AxNiR, BRAO375_2740002, C551-O2 oxidoreductase, cd1 nitrite reductase, cd1NiR, cNOR, copper-containing dissimilatory nitrite reductase, copper-containing nitrite reductase, Cu-NIR, Cu-NirK, CuNIR, cytochrome c-551:O2, NO2- oxidoreductase, cytochrome cd, cytochrome cd1 nitrite reductase, cytochrome oxidase, dissimilatory nitrite reductase, dissimilatory nitrite reductase cytochrome cd1, EC 1.6.6.5, EC 1.7.99.3, EC 1.9.3.2, GK0767, GtNiR, HdNIR, hemoglobin, HydNIR, HYPDE_25578, KSU1_D0929, mARC1, mARC2, mitochondrial amidoxime reducing component, MRA2164, NiR, NiR-Pa, NirK, NirS, nitrite reductase, oxidase, Pseudomonas cytochrome, PaNiR, PNR, Pseudomonas cytochrome oxidase, PsNiR, reductase, nitrite (cytochrome), Rpic_4015, S58_68210
ECTree
1.7.2.1 nitrite reductase (NO-forming)Advanced search results
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results (Engineering
Engineering on EC 1.7.2.1 - nitrite reductase (NO-forming)
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PROTEIN VARIANTS 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
W144L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
W144L/Y203L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
Y203L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
W144L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
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W144L/Y203L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
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Y203L
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visible absorption and EPR spectrum is similar to that of wild-type AcNIR. The redox potentials of the mutant is also nearly equal to that of wild-type. Although the enzymatic activities of the mutants are also the same as that of wild-type enzyme, the intermolecular electron transfer rate constants from pseudoazurin to mutant AcNIRs is 3-4fold less than that from pseudoazurin to wild-type AcNIR using electrochemical methods
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A83D/A191E/G198E
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4.7fold increase in electron transfer rate constant
C130A
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inactive mutant enzyme, the loss of activity in this mutant is due to the absence of T1Cu and loss of the CuCys130Sg bond rather than any change to the protein structure in this region
D92E
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mutation in type 2 Cu center, very low activity with artificial electron donors methyl viologen and sodium dithionite, 20-30% of wild-type activity with physiological electron donor azurin I
D92N
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mutation in type 2 Cu center, very low activity with artificial electron donors methyl viologen and sodium dithionite, 60-70% of wild-type activity with physiological electron donor azurin I
H139A
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mutation in type 1 Cu center, very low activity with the artificial electron donor methyl viologen, no activity with the physiological electron donor azurin I
H254F
full catalytic activity despite disruption of the primary proton channel. No change in apparent Km value for nitrite
M144L
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change in activity in the mutant is related to the perturbation of the finely poised redox potentials of the T1Cu sites of azurin and AxNiR
M144Q
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change in activity in the mutant is related to the perturbation of the finely poised redox potentials of the T1Cu sites of azurin and AxNiR
N90S
disruption of H-bonding in the high-pH proton channel results in an 70% decrease in specific activity. No change in apparent Km value for nitrite
M150G
M150T
M150G
M150T
C43S
mutation leads to disruption of a disulfide bridge. Mutant is a trimer in solution and shows similar spectroscopic properties and enzymatic activity as the wild-type using dithionite as reductant. The kcat values of C43S mutant decrease to about 20% of wild-type when reduced B0428 is used as an electron donor
C135A
C273A
mutation in the putative active site cysteine residue, known to coordinate molybdenum binding. NO formation is abolished by the C273A mutation
C114A
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lacks the type I copper ion in the N-terminal domain, shows catalytic activity
C260A
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lacks the type I copper ion in the C-terminal domain, no nitrite-reduction activity
C114A
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lacks the type I copper ion in the N-terminal domain, shows catalytic activity
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C260A
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lacks the type I copper ion in the C-terminal domain, no nitrite-reduction activity
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H280L
a naturally occuring, enzyme-inactivating mutation in the disease-associated strain i1332, a 9-residues insertion located close to the type I Cu-site and mutation of the catalytic histidine at position 280
M106H
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inactive protein, the unusual highly cooperative and strongly hysteretic redox titration of the wild-type is lost in the mutant protein
Y25S
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unlike the wild-type enzyme, the Y25S mutant is active as a reductase toward nitrite, O2, and hydroxylamine without a reduuctive activation step
H327A
H369A
Y10F
Y323A
about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. The water molecules occupying free space above type 2 copper are connected by strong hydrogen bonds, while the channel space, opposite to the NiR-core, is open and contains full occupancy waters
Y323E
about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. The water molecules occupying free space above type 2 copper are connected by strong hydrogen bonds, while the channel space, opposite to the NiR-core, is open and contains full occupancy waters
Y323F
about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. Mutant has a single water, W1, bound to the type 2 copper site
Y323A
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about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. The water molecules occupying free space above type 2 copper are connected by strong hydrogen bonds, while the channel space, opposite to the NiR-core, is open and contains full occupancy waters
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Y323E
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about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. The water molecules occupying free space above type 2 copper are connected by strong hydrogen bonds, while the channel space, opposite to the NiR-core, is open and contains full occupancy waters
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Y323F
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about 90% of wild-type activity. Tether residue Tyr 323 is a gatekeeper for nitrite binding. Mutant has a single water, W1, bound to the type 2 copper site
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additional information
M150G
mutant enzyme shows lower catalytic activity than the wild-type enzyme. The type-1 site optical spectrum differs significantly from that of the native enzyme. The midpoint potential of the type-1 site of nitrite reductase M150G is higher than that of the native enzyme
M150G
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mutation increases the reorganization energy by 0.3 eV (30 kJ/mol), binding of the nearby Met62 to the type-1 Cu site lowers the reorganization energy back to approximately the wild-type value
M150T
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mutant enzyme has a type-1 site with a 125-mV higher midpoint potential and a 0.3-eV higher reorganization energy leading to an about 50-fold slower intramolecular electrontransfer to the type-2 site
M150T
mutant enzyme shows lower catalytic activity than the wild-type enzyme
M150T
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mutation increases the reorganization energy by 0.3 eV (30 kJ/mol)
M150G
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mutation increases the reorganization energy by 0.3 eV (30 kJ/mol), binding of the nearby Met62 to the type-1 Cu site lowers the reorganization energy back to approximately the wild-type value
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M150G
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mutant enzyme shows lower catalytic activity than the wild-type enzyme. The type-1 site optical spectrum differs significantly from that of the native enzyme. The midpoint potential of the type-1 site of nitrite reductase M150G is higher than that of the native enzyme
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M150T
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mutation increases the reorganization energy by 0.3 eV (30 kJ/mol)
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M150T
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mutant enzyme shows lower catalytic activity than the wild-type enzyme
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C135A
mutant structure analysis, nitrite bound to the T2 Cu site in the eta1-O end-on form, structure analysis, PDB ID 3WKP
C135A
site-directed mutagenesis, the crystal structure of mutant C135A with nitrite displays a unique eta1-O coordination mode of nitrite at the catalytic copper site (T2Cu) unlike the wild-type enzyme
C135A
in the anaerobic synchrotron-radiation crystallography structure with peroxide bound to the type 2 copper atom, the peroxide molecule is mainly observed in a side-on binding manner, with a possible minor end-on conformation
C135A
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mutant structure analysis, nitrite bound to the T2 Cu site in the eta1-O end-on form, structure analysis, PDB ID 3WKP
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C135A
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site-directed mutagenesis, the crystal structure of mutant C135A with nitrite displays a unique eta1-O coordination mode of nitrite at the catalytic copper site (T2Cu) unlike the wild-type enzyme
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H327A
mutant protein has no nitrite reductase activity but maintains the ability to reduce O2 to water. Nitrite reductase activity is impaired because of the accumulation of a catalytically inactive form
H327A
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the three-dimensional structures of NIR mutant H327A, and H369A in complex with NO solved by multiple wave-length anomalous dispersion, using the iron anomalous signal, and molecular replacement techniques. In both refined crystal structures the c-heme domain, whilst preserving its classical c-type cytochrome fold, has undergone a 60° rigid-body rotation around an axis parallel with the pseudo 8-fold axis of the beta-propeller, and passing through residue Gln115. Even though the distance between the Fe ions of the c and d1-heme remains 21 A, the edge-to-edge distance between the two hemes has increased by 5 A. Furthermore the distal side of the d1-heme pocket appears to have undergone structural re-arrangement and Tyr10 has moved out of the active site. In the H369A-NO complex, the position and orientation of NO is significantly different from that of the NO bound to the reduced wild-type structure
H369A
mutant protein has no nitrite reductase activity but maintains the ability to reduce O2 to water. Nitrite reductase activity is impaired because of the accumulation of a catalytically inactive form
H369A
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the three-dimensional structures of NIR mutant H327A, and H369A in complex with NO solved by multiple wave-length anomalous dispersion, using the iron anomalous signal, and molecular replacement techniques. In both refined crystal structures the c-heme domain, whilst preserving its classical c-type cytochrome fold, has undergone a 60° rigid-body rotation around an axis parallel with the pseudo 8-fold axis of the beta-propeller, and passing through residue Gln115. Even though the distance between the Fe ions of the c and d1-heme remains 21 A, the edge-to-edge distance between the two hemes has increased by 5 A. Furthermore the distal side of the d1-heme pocket appears to have undergone structural re-arrangement and Tyr10 has moved out of the active site. In the H369A-NO complex, the position and orientation of NO is significantly different from that of the NO bound to the reduced wild-type structure
H369A
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mutation impairs the reaction with O2, affecting both the properties and lifespan of the intermediate species
Y10F
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no change in optical spectrum, nitrite and oxidase activity and heme c to heme d1 electron transfer rates compared to wild-type
Y10F
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high-field-pulse electron papramagnetic spectroscopy spectra and the derived 14N hyperfine and quadrupole interactions are the same for wild-type and mutant. Residue Y10 does not influence the NO ligand orientation in the reduced state in solution
additional information
replacement of the long 15-residue type 1 copper-binding loop of nitrite reductase with that from Paracoccus versutus cupredoxin amicyanin. The sizable loop contraction does not have a significant effect on the structures of both the type 1 and type 2 CuII sites. The crystal structure of the variant with ZnII at both the type 1 and type 2 sites shows a coordination geometry of the type 2 site that is almost identical to that found in the wild-type protein. In the type 1 centre, the positions of most of the coordinating residues are altered with the largest difference observed for the coordinating His residue in the centre of the mutated loop. This ligand moves away from the active site, which results in a more open metal centre with a coordinating water molecule. The reduction potential of the type i centre is reduced by 200 mV. The resulting unfavourable driving force for electron transfer between the two copper sites, and an increased reorganisation energy for the type 1 centre, contribute to the loop variant having very little nitrite reductase activity
additional information
construction of domain-truncated mutants lacking the Cyt c (18% of wild-type activity) and the Cyt c-Cup domains (3fold increase in activity)
additional information
the core type 1 copper mutant displays a long-range electron tunneling route via a hydrophobic beta-strand, thereby bypassing the type 1 copper core and delivering electrons directly to the catalytic type 2 copper center
additional information
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the core type 1 copper mutant displays a long-range electron tunneling route via a hydrophobic beta-strand, thereby bypassing the type 1 copper core and delivering electrons directly to the catalytic type 2 copper center
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