Structural insights into the molecular mechanism of H-NOX activation

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.217 

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Structural insights into the molecular mechanism of H-NOX activation.

Olea, C.Herzik, M.A.Kuriyan, J.Marletta, M.A.

(2010) Protein Sci 19: 881-887

  • DOI: https://doi.org/10.1002/pro.357
  • Primary Citation of Related Structures:  
    3LAH, 3LAI

  • PubMed Abstract: 

    Nitric oxide (NO) signaling in mammals controls important processes such as smooth muscle relaxation and neurotransmission by the activation of soluble guanylate cyclase (sGC). NO binding to the heme domain of sGC leads to dissociation of the iron-histidine (Fe-His) bond, which is required for enzyme activity. The heme domain of sGC belongs to a larger class of proteins called H-NOX (Heme-Nitric oxide/OXygen) binding domains. Previous crystallographic studies on H-NOX domains demonstrate a correlation between heme bending and protein conformation. It was unclear, however, whether these structural changes were important for signal transduction. Subsequent NMR solution structures of H-NOX proteins show a conformational change upon disconnection of the heme and proximal helix, similar to those observed in the crystallographic studies. The atomic details of these conformational changes, however, are lacking in the NMR structures especially at the heme pocket. Here, a high-resolution crystal structure of an H-NOX mutant mimicking a broken Fe-His bond is reported. This mutant exhibits specific changes in heme conformation and major N-terminal displacements relative to the wild-type H-NOX protein. Fe-His ligation is ubiquitous in all H-NOX domains, and therefore, the heme and protein conformational changes observed in this study are likely to occur throughout the H-NOX family when NO binding leads to rupture of the Fe-His bond.

  • Organizational Affiliation

    Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Methyl-accepting chemotaxis protein
A, B
188Caldanaerobacter subterraneus subsp. tengcongensisMutation(s): 1 
Gene Names: Tar4TTE0680
Find proteins for Q8RBX6 (Caldanaerobacter subterraneus subsp. tengcongensis (strain DSM 15242 / JCM 11007 / NBRC 100824 / MB4))
Explore Q8RBX6 
Go to UniProtKB:  Q8RBX6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8RBX6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.215 
  • R-Value Observed: 0.217 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.353α = 90
b = 88.713β = 90
c = 89.207γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-03-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-13
    Changes: Database references, Derived calculations
  • Version 1.3: 2024-02-21
    Changes: Data collection