Publication Date:
1998-04-16
Description:
Crystal structures of the murine cytokine-inducible nitric oxide synthase oxygenase dimer with active-center water molecules, the substrate L-arginine (L-Arg), or product analog thiocitrulline reveal how dimerization, cofactor tetrahydrobiopterin, and L-Arg binding complete the catalytic center for synthesis of the essential biological signal and cytotoxin nitric oxide. Pterin binding refolds the central interface region, recruits new structural elements, creates a 30 angstrom deep active-center channel, and causes a 35 degrees helical tilt to expose a heme edge and the adjacent residue tryptophan-366 for likely reductase domain interactions and caveolin inhibition. Heme propionate interactions with pterin and L-Arg suggest that pterin has electronic influences on heme-bound oxygen. L-Arginine binds to glutamic acid-371 and stacks with heme in an otherwise hydrophobic pocket to aid activation of heme-bound oxygen by direct proton donation and thereby differentiate the two chemical steps of nitric oxide synthesis.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Crane, B R -- Arvai, A S -- Ghosh, D K -- Wu, C -- Getzoff, E D -- Stuehr, D J -- Tainer, J A -- HL58883/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1998 Mar 27;279(5359):2121-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9516116" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Arginine/chemistry/*metabolism
;
Binding Sites
;
Biopterin/*analogs & derivatives/chemistry/metabolism
;
Citrulline/analogs & derivatives/chemistry/metabolism
;
Crystallography, X-Ray
;
Dimerization
;
Hydrogen Bonding
;
Isoenzymes/chemistry/metabolism
;
Ligands
;
Macrophages/enzymology
;
Mice
;
Models, Molecular
;
Nitric Oxide/biosynthesis
;
Nitric Oxide Synthase/*chemistry/metabolism
;
Nitric Oxide Synthase Type II
;
*Protein Conformation
;
Protein Folding
;
Protein Structure, Secondary
;
Thiourea/analogs & derivatives/chemistry/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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