1DWX

MURINE INDUCIBLE NITRIC OXIDE SYNTHASE OXYGENASE DIMER N-hydroxyarginine and tetrahydrobiopterin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.238 
  • R-Value Observed: 0.238 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Structures of the N(Omega)-Hydroxy-L-Arginine Complex of Inducible Nitric Oxide Synthase Oxygenase Dimer with Active Andinactive Pterins

Crane, B.R.Arvai, A.S.Ghosh, S.Getzoff, E.D.Stuehr, D.J.Tainer, J.A.

(2000) Biochemistry 39: 4608

  • DOI: https://doi.org/10.1021/bi992409a
  • Primary Citation of Related Structures:  
    1DWV, 1DWW, 1DWX

  • PubMed Abstract: 

    Nitric oxide synthases (NOSs) catalyze two mechanistically distinct, tetrahydrobiopterin (H(4)B)-dependent, heme-based oxidations that first convert L-arginine (L-Arg) to N(omega)-hydroxy-L-arginine (NHA) and then NHA to L-citrulline and nitric oxide. Structures of the murine inducible NOS oxygenase domain (iNOS(ox)) complexed with NHA indicate that NHA and L-Arg both bind with the same conformation adjacent to the heme iron and neither interacts directly with it nor with H(4)B. Steric restriction of dioxygen binding to the heme in the NHA complex suggests either small conformational adjustments in the ternary complex or a concerted reaction of dioxygen with NHA and the heme iron. Interactions of the NHA hydroxyl with active center beta-structure and the heme ring polarize and distort the hydroxyguanidinium to increase substrate reactivity. Steric constraints in the active center rule against superoxo-iron accepting a hydrogen atom from the NHA hydroxyl in their initial reaction, but support an Fe(III)-peroxo-NHA radical conjugate as an intermediate. However, our structures do not exclude an oxo-iron intermediate participating in either L-Arg or NHA oxidation. Identical binding modes for active H(4)B, the inactive quinonoid-dihydrobiopterin (q-H(2)B), and inactive 4-amino-H(4)B indicate that conformational differences cannot explain pterin inactivity. Different redox and/or protonation states of q-H(2)B and 4-amino-H(4)B relative to H(4)B likely affect their ability to electronically influence the heme and/or undergo redox reactions during NOS catalysis. On the basis of these structures, we propose a testable mechanism where neutral H(4)B transfers both an electron and a 3,4-amide proton to the heme during the first step of NO synthesis.


  • Organizational Affiliation

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


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
NITRIC OXIDE SYNTHASE
A, B
420Mus musculusMutation(s): 0 
EC: 1.14.13.39
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
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.238 
  • R-Value Observed: 0.238 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 212.98α = 90
b = 212.98β = 90
c = 114.2γ = 120
Software Package:
Software NamePurpose
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-02-06
    Type: Initial release
  • Version 1.1: 2011-05-07
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance