View source for 2o09

[[Image:2o09.gif|left|200px]]

 {{Structure
|PDB= 2o09 |SIZE=350|CAPTION= <scene name='initialview01'>2o09</scene>, resolution 2.100&Aring;
|SITE= 
|LIGAND= <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>
|ACTIVITY= 
|GENE= alr2278 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1167 Anabaena sp.])
|DOMAIN=
|RELATEDENTRY=[[2o0c|2O0C]], [[2o0g|2O0G]]
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2o09 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2o09 OCA], [http://www.ebi.ac.uk/pdbsum/2o09 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2o09 RCSB]</span>
}}

'''Crystal structure of the H-NOX domain from Nostoc sp. PCC 7120'''


==Overview==
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.

==About this Structure==
2O09 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Anabaena_sp. Anabaena sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2O09 OCA]. 

==Reference==
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:[http://www.ncbi.nlm.nih.gov/pubmed/17215864 17215864]
[[Category: Anabaena sp.]]
[[Category: Single protein]]
[[Category: Akker, F van den.]]
[[Category: Ma, X.]]
[[Category: co]]
[[Category: guanylyl cyclase]]
[[Category: heme]]
[[Category: no]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 04:10:53 2008''