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spinqualitylabelsall models 1q2o, resolution 1.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Bovine endothelial nitric oxide synthase N368D mutant heme domain dimer with L-N(omega)-nitroarginine-2,4-L-diaminobutyramide bound

Overview

Three nitric oxide synthase (NOS) isoforms, eNOS, nNOS and iNOS, generate nitric oxide (NO) crucial to the cardiovascular, nervous and host defense systems, respectively. Development of isoform-selective NOS inhibitors is of considerable therapeutic importance. Crystal structures of nNOS-selective dipeptide inhibitors in complex with both nNOS and eNOS were solved and the inhibitors were found to adopt a curled conformation in nNOS but an extended conformation in eNOS. We hypothesized that a single-residue difference in the active site, Asp597 (nNOS) versus Asn368 (eNOS), is responsible for the favored binding in nNOS. In the D597N nNOS mutant crystal structure, a bound inhibitor switches to the extended conformation and its inhibition of nNOS decreases >200-fold. Therefore, a single-residue difference is responsible for more than two orders of magnitude selectivity in inhibition of nNOS over eNOS by L-N(omega)-nitroarginine-containing dipeptide inhibitors.

About this Structure

1Q2O is a Single protein structure of sequence from Bos taurus with , , , , , and as ligands. Active as Nitric-oxide synthase, with EC number 1.14.13.39 Full crystallographic information is available from OCA.

Reference

Structural basis for dipeptide amide isoform-selective inhibition of neuronal nitric oxide synthase., Flinspach ML, Li H, Jamal J, Yang W, Huang H, Hah JM, Gomez-Vidal JA, Litzinger EA, Silverman RB, Poulos TL, Nat Struct Mol Biol. 2004 Jan;11(1):54-9. Epub 2003 Dec 29. PMID:14718923

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