2fbz: Difference between revisions

Revision as of 03:42, 4 May 2008

Heme-No complex in a bacterial Nitric Oxide Synthase

OverviewOverview

The crystal structures of nitrosyl-heme complexes of a prokaryotic nitric oxide synthase (NOS) from Bacillus subtilis (bsNOS) reveal changes in active-site hydrogen bonding in the presence of the intermediate N(omega)-hydroxy-l-arginine (NOHA) compared to the substrate l-arginine (l-Arg). Correlating with a Val-to-Ile residue substitution in the bsNOS heme pocket, the Fe(II)-NO complex with both l-Arg and NOHA is more bent than the Fe(II)-NO, l-Arg complex of mammalian eNOS [Li, H., Raman, C. S., Martasek, P., Masters, B. S. S., and Poulos, T. L. (2001) Biochemistry 40, 5399-5406]. Structures of the Fe(III)-NO complex with NOHA show a nearly linear nitrosyl group, and in one subunit, partial nitrosation of bound NOHA. In the Fe(II)-NO complexes, the protonated NOHA N(omega) atom forms a short hydrogen bond with the heme-coordinated NO nitrogen, but active-site water molecules are out of hydrogen bonding range with the distal NO oxygen. In contrast, the l-Arg guanidinium interacts more weakly and equally with both NO atoms, and an active-site water molecule hydrogen bonds to the distal NO oxygen. This difference in hydrogen bonding to the nitrosyl group by the two substrates indicates that interactions provided by NOHA may preferentially stabilize an electrophilic peroxo-heme intermediate in the second step of NOS catalysis.

About this StructureAbout this Structure

2FBZ is a Single protein structure of sequence from Bacillus subtilis. Full crystallographic information is available from OCA.

ReferenceReference

Nitrosyl-heme structures of Bacillus subtilis nitric oxide synthase have implications for understanding substrate oxidation., Pant K, Crane BR, Biochemistry. 2006 Feb 28;45(8):2537-44. PMID:16489746 Page seeded by OCA on Sun May 4 03:42:41 2008

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OCA

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 [[Image:2fbz.gif|left|200px]]
- {{Structure
+<!--
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+The line below this paragraph, containing "STRUCTURE_2fbz", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=H2B:2-AMINO-6-(1,2-DIHYDROXY-PROPYL)-7,8-DIHYDRO-6H-PTERIDIN-4-ONE'>H2B</scene>, <scene name='pdbligand=HAR:N-OMEGA-HYDROXY-L-ARGININE'>HAR</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=NO:NITROGEN+OXIDE'>NO</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY=
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-|GENE= nos ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1423 Bacillus subtilis])
+-->
-|DOMAIN=
+{{STRUCTURE_2fbz|  PDB=2fbz  |  SCENE=  }}
-|RELATEDENTRY=[[1m7z|1M7Z]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2fbz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2fbz OCA], [http://www.ebi.ac.uk/pdbsum/2fbz PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2fbz RCSB]</span>
-}}
 '''Heme-No complex in a bacterial Nitric Oxide Synthase'''
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 [[Category: Crane, B R.]]
 [[Category: Pant, K.]]
-[[Category: heme-no complex]]
+[[Category: Heme-no complex]]
-[[Category: nitric oxide synthase]]
+[[Category: Nitric oxide synthase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 03:42:41 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:00:44 2008''