2PPD

Oxidized H145A mutant of AfNiR bound to nitric oxide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.189 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Stable copper-nitrosyl formation by nitrite reductase in either oxidation state

Tocheva, E.I.Rosell, F.I.Mauk, A.G.Murphy, M.E.

(2007) Biochemistry 46: 12366-12374

  • DOI: https://doi.org/10.1021/bi701205j
  • Primary Citation of Related Structures:  
    2PPC, 2PPD, 2PPE, 2PPF

  • PubMed Abstract: 

    Nitrite reductase (NiR) is an enzyme that uses type 1 and type 2 copper sites to reduce nitrite to nitric oxide during bacterial denitrification. A copper-nitrosyl intermediate is a proposed, yet poorly characterized feature of the NiR catalytic cycle. This intermediate is formally described as Cu(I)-NO+ and is proposed to be formed at the type 2 copper site after nitrite binding and electron transfer from the type 1 copper site. In this study, copper-nitrosyl complexes were formed by prolonged exposure of exogenous NO to crystals of wild-type and two variant forms of NiR from Alcaligenes faecalis (AfNiR), and the structures were determined to 1.8 A or better resolution. Exposing oxidized wild-type crystals to NO results in the reverse reaction and formation of nitrite that remains bound at the active site. In a type 1 copper site mutant (H145A) that is incapable of electron transfer to the type 2 site, the reverse reaction is not observed. Instead, in both oxidized and reduced H145A crystals, NO is observed bound in a side-on manner to the type 2 copper. In AfNiR, Asp98 forms hydrogen bonds to both substrate and product bound to the type 2 Cu. In the D98N variant, NO is bound side-on but is more disordered when observed for the wild-type enzyme. The solution EPR spectra of the crystallographically characterized NiR-NO complexes indicate the presence of an oxidized type 2 copper site and thus are interpreted as resulting from stable copper-nitrosyls and formally assigned as Cu(II)-NO-. A reaction scheme in which a second NO molecule is oxidized to nitrite can account for the formation of a Cu(II)-NO- species after exposure of the oxidized H145A variant to NO gas.


  • Organizational Affiliation

    Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC, V6T 1Z3, Canada.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Copper-containing nitrite reductase
A, B, C
343Alcaligenes faecalisMutation(s): 1 
Gene Names: nirKnir
EC: 1.7.2.1
UniProt
Find proteins for P38501 (Alcaligenes faecalis)
Explore P38501 
Go to UniProtKB:  P38501
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP38501
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
TRS
Query on TRS

Download Ideal Coordinates CCD File 
G [auth A]2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL
C4 H12 N O3
LENZDBCJOHFCAS-UHFFFAOYSA-O
CU
Query on CU

Download Ideal Coordinates CCD File 
E [auth A],
I [auth B],
M [auth C]
COPPER (II) ION
Cu
JPVYNHNXODAKFH-UHFFFAOYSA-N
CU1
Query on CU1

Download Ideal Coordinates CCD File 
D [auth A],
H [auth B],
L [auth C]
COPPER (I) ION
Cu
VMQMZMRVKUZKQL-UHFFFAOYSA-N
ACT
Query on ACT

Download Ideal Coordinates CCD File 
J [auth B]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
NO
Query on NO

Download Ideal Coordinates CCD File 
F [auth A],
K [auth B]
NITRIC OXIDE
N O
ODUCDPQEXGNKDN-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.189 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.957α = 90
b = 102.062β = 90
c = 145.797γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
AMoREphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.3: 2024-02-21
    Changes: Data collection