Structural basis for dipeptide amide isoform-selective inhibition of neuronal nitric oxide synthase.Flinspach, M.L., Li, H., Jamal, J., Yang, W., Huang, H., Hah, J.M., Gomez-Vidal, J.A., Litzinger, E.A., Silverman, R.B., Poulos, T.L.
(2004) Nat Struct Mol Biol 11: 54-59
- PubMed: 14718923
- DOI: https://doi.org/10.1038/nsmb704
- Primary Citation of Related Structures:
1P6H, 1P6I, 1P6J, 1P6K, 1P6L, 1P6M, 1P6N, 1Q2O
- PubMed Abstract:
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.
Department of Molecular Biology and Biochemistry and the Program in Macromolecular Structure, University of California, Irvine, California 92697-3900, USA.