2O0C

Crystal structure of the H-NOX domain from Nostoc sp. PCC 7120 complexed to NO

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.195 

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


Literature

NO and CO differentially activate soluble guanylyl cyclase via a heme pivot-bend mechanism.

Ma, X., Sayed, N., Beuve, A., van den Akker, F.

(2007) EMBO J 26: 578-588

  • DOI: 10.1038/sj.emboj.7601521
  • Primary Citation of Related Structures:  
    2O09, 2O0C, 2O0G

  • PubMed Abstract: 

    • Diatomic ligand discrimination by soluble guanylyl cyclase (sGC) is paramount to cardiovascular homeostasis and neuronal signaling. Nitric oxide (NO) stimulates sGC activity 200-fold compared with only four-fold by carbon monoxide (CO). The molecular details of ligand discrimination and differential response to NO and CO are not well understood ...

    Diatomic ligand discrimination by soluble guanylyl cyclase (sGC) is paramount to cardiovascular homeostasis and neuronal signaling. Nitric oxide (NO) stimulates sGC activity 200-fold compared with only four-fold by carbon monoxide (CO). The molecular details of ligand discrimination and differential response to NO and CO are not well understood. These ligands are sensed by the heme domain of sGC, which belongs to the heme nitric oxide oxygen (H-NOX) domain family, also evolutionarily conserved in prokaryotes. Here we report crystal structures of the free, NO-bound, and CO-bound H-NOX domains of a cyanobacterial homolog. These structures and complementary mutational analysis in sGC reveal a molecular ruler mechanism that allows sGC to favor NO over CO while excluding oxygen, concomitant to signaling that exploits differential heme pivoting and heme bending. The heme thereby serves as a flexing wedge, allowing the N-terminal subdomain of H-NOX to shift concurrent with the transition of the six- to five-coordinated NO-bound state upon sGC activation. This transition can be modulated by mutations at sGC residues 74 and 145 and corresponding residues in the cyanobacterial H-NOX homolog.

    Organizational Affiliation: 

    Department of Biochemistry/RT500, Case Western Reserve University, Cleveland, OH 44106, USA.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Alr2278 proteinA, B189Nostoc sp. PCC 7120 = FACHB-418Mutation(s): 0 
Gene Names: alr2278
UniProt
Find proteins for Q8YUQ7 (Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576))
Explore Q8YUQ7 
Go to UniProtKB:  Q8YUQ7
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8YUQ7
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM
Download Ideal Coordinates CCD File 
C [auth A],
E [auth B]		PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L		 Ligand Interaction
NO
Query on NO
Download Ideal Coordinates CCD File 
D [auth A],
F [auth B]		NITRIC OXIDE
N O
ODUCDPQEXGNKDN-UHFFFAOYAM		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.195 
  • Space Group: P 21 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 123.564α = 90
b = 123.564β = 90
c = 123.564γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-01-30
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Source and taxonomy, Version format compliance