1ET8

CRYSTAL STRUCTURE OF NITRITE REDUCTASE HIS255ASN MUTANT FROM ALCALIGENES FAECALIS

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 

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This is version 1.2 of the entry. See complete history. 


Literature

Catalytic roles for two water bridged residues (Asp-98 and His-255) in the active site of copper-containing nitrite reductase.

Boulanger, M.J., Kukimoto, M., Nishiyama, M., Horinouchi, S., Murphy, M.E.

(2000) J Biol Chem 275: 23957-23964

  • DOI: 10.1074/jbc.M001859200
  • Primary Citation of Related Structures:  
    1ET7, 1ET5, 1ET8

  • PubMed Abstract: 

    • Two active site residues, Asp-98 and His-255, of copper-containing nitrite reductase (NIR) from Alcaligenes faecalis have been mutated to probe the catalytic mechanism. Three mutations at these two sites (D98N, H255D, and H255N) result in large reduc ...

    Two active site residues, Asp-98 and His-255, of copper-containing nitrite reductase (NIR) from Alcaligenes faecalis have been mutated to probe the catalytic mechanism. Three mutations at these two sites (D98N, H255D, and H255N) result in large reductions in activity relative to native NIR, suggesting that both residues are involved intimately in the reaction mechanism. Crystal structures of these mutants have been determined using data collected to better than 1. 9-A resolution. In the native structure, His-255 Nepsilon2 forms a hydrogen bond through a bridging water molecule to the side chain of Asp-98, which also forms a hydrogen bond to a water or nitrite oxygen ligated to the active site copper. In the D98N mutant, reorientation of the Asn-98 side chain results in the loss of the hydrogen bond to the copper ligand water, consistent with a negatively charged Asp-98 directing the binding and protonation of nitrite in the native enzyme. An additional solvent molecule is situated between residues 255 and the bridging water in the H255N and H255D mutants and likely inhibits nitrite binding. The interaction of His-255 with the bridging water appears to be necessary for catalysis and may donate a proton to reaction intermediates in addition to Asp-98.

    Organizational Affiliation: 

    Departments of Biochemistry and Molecular Biology and of Microbiology and Immunology, University of British Columbia, Vancouver V6T 1Z3, Canada.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
NITRITE REDUCTASEA341Alcaligenes faecalisMutation(s): 1 
Gene Names: nirK, nir
EC: 1.7.99.3 (PDB Primary Data), 1.7.2.1 (UniProt)
Find proteins for P38501 (Alcaligenes faecalis)
Explore P38501 
Go to UniProtKB:  P38501
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN
Download Ideal Coordinates CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N		 Ligand Interaction
CU
Query on CU
Download Ideal Coordinates CCD File 
A
COPPER (II) ION
Cu
JPVYNHNXODAKFH-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 127.659α = 90
b = 127.659β = 90
c = 67.215γ = 120
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-08-24
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance