2O0C

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


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, 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 ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Alr2278 protein
A, B
189Nostoc sp. (strain PCC 7120 / UTEX 2576)N/A
Find proteins for Q8YUQ7 (Nostoc sp. (strain PCC 7120 / UTEX 2576))
Go to UniProtKB:  Q8YUQ7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
NO
Query on NO

Download SDF File 
Download CCD File 
A, B
NITRIC OXIDE
Nitrogen monoxide
N O
ODUCDPQEXGNKDN-UHFFFAOYAM
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.192 
  • Space Group: P 21 3
Unit Cell:
Length (Å)Angle (°)
a = 123.564α = 90.00
b = 123.564β = 90.00
c = 123.564γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-2000data reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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