2o0c

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

spinqualitylabelsall models 2o0c, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2o0c is a 2 chain structure with sequence from Nostoc sp. PCC 7120 = FACHB-418. The January 2011 RCSB PDB Molecule of the Month feature on Nitric Oxide Synthase by David Goodsell is 10.2210/rcsb_pdb/mom_2011_1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.6Å Ligands: HEM, NO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q8YUQ7_NOSS1 Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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. NO and CO differentially activate soluble guanylyl cyclase via a heme pivot-bend mechanism.,Ma X, Sayed N, Beuve A, van den Akker F EMBO J. 2007 Jan 24;26(2):578-88. Epub 2007 Jan 11. PMID:17215864 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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