Murine Inducible Nitric Oxide Synthase Oxygenase Dimer (Delta 65) with W457F Mutation at Tetrahydrobiopterin Binding Site

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 

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Structures of tetrahydrobiopterin binding-site mutants of inducible nitric oxide synthase oxygenase dimer and implicated roles of Trp457.

Aoyagi, M.Arvai, A.S.Ghosh, S.Stuehr, D.J.Tainer, J.A.Getzoff, E.D.

(2001) Biochemistry 40: 12826-12832

  • DOI: https://doi.org/10.1021/bi011183k
  • Primary Citation of Related Structures:  
    1JWJ, 1JWK

  • PubMed Abstract: 

    To better understand potential roles of conserved Trp457 of the murine inducible nitric oxide synthase oxygenase domain (iNOS(ox); residues 1-498) in maintaining the structural integrity of the (6R)-5,6,7,8-tetrahydrobiopterin (H(4)B) binding site located at the dimer interface and in supporting H(4)B redox activity, we determined crystallographic structures of W457F and W457A mutant iNOS(ox) dimers (residues 66-498). In W457F iNOS(ox), all the important hydrogen-bonding and aromatic stacking interactions that constitute the H(4)B binding site and that bridge the H(4)B and heme sites are preserved. In contrast, the W457A mutation results in rearrangement of the Arg193 side chain, orienting its terminal guanidinium group almost perpendicular to the ring plane of H(4)B. Although Trp457 is not required for dimerization, both Trp457 mutations led to the increased mobility of the N-terminal H(4)B binding segment (Ser112-Met114), which might indicate reduced stability of the Trp457 mutant dimers. The Trp457 mutant structures show decreased pi-stacking with bound pterin when the wild-type pi-stacking Trp457 position is occupied with the smaller Phe457 in W457F or positive Arg193 in W457A. The reduced pterin pi-stacking in these mutant structures, relative to that in the wild-type, implies stabilization of reduced H(4)B and destabilization of the pterin radical, consequently slowing electron transfer to the heme ferrous-dioxy (Fe(II)O(2)) species during catalysis. These crystal structures therefore aid elucidation of the roles and importance of conserved Trp457 in maintaining the structural integrity of the H(4)B binding site and of H(4)B-bound dimers, and in influencing the rate of electron transfer between H(4)B and heme in NOS catalysis.

  • Organizational Affiliation

    Department of Molecular Biology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitric Oxide Synthase
A, B
433Mus musculusMutation(s): 1 
UniProt & NIH Common Fund Data Resources
Find proteins for P29477 (Mus musculus)
Explore P29477 
Go to UniProtKB:  P29477
IMPC:  MGI:97361
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29477
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HEM

Download Ideal Coordinates CCD File 
D [auth A],
J [auth B]
C34 H32 Fe N4 O4
Query on BOG

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C [auth A],
I [auth B]
octyl beta-D-glucopyranoside
C14 H28 O6
Query on H4B

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E [auth A],
K [auth B]
C9 H15 N5 O3
Query on GOL

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F [auth A]
G [auth A]
H [auth A]
N [auth B]
O [auth B]
F [auth A],
G [auth A],
H [auth A],
N [auth B],
O [auth B],
P [auth B],
Q [auth B],
R [auth B],
S [auth B]
C3 H8 O3
Query on EDO

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L [auth B],
M [auth B]
C2 H6 O2
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.218 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 213.603α = 90
b = 213.603β = 90
c = 116.892γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-10-31
    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
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.4: 2021-10-27
    Changes: Database references, Structure summary
  • Version 1.5: 2023-08-16
    Changes: Data collection, Refinement description