L337H Mutant of Rat Neuronal Nitric Oxide Synthase Resembles Human Neuronal Nitric Oxide Synthase toward Inhibitors
ABSTRACT A common dichotomy exists in inhibitor design: should the compounds be designed to block the enzymes of animals in the preclinical studies or to inhibit the human enzyme? We report that a single mutation of Leu-337 in rat neuronal nitric oxide synthase (nNOS) to His makes the enzyme resemble human nNOS more than rat nNOS. We expect that the approach used in this study can unite the dichotomy and speed up the process of inhibitor design and development.
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ABSTRACT: A novel series of (2-amino)-6-(2-aminoethyl)pyridines were prepared by a convenient Suzuki–Miyaura coupling approach from 2-amino-6-bromopyridines. Benzyl vinylcarbamate was first treated with 9-BBN followed by aqueous NaOH and then the appropriate bromopyridine precursors were added into the mixture. The mixture was finally heated in presence of a palladium catalyst to provide the corresponding products in overall high yields. The procedure is extended to the preparation of related pyrazine and pyrimidine compounds as well as (2-amido)- and (2-alkoxy)-6-(2-aminoethyl)pyridines.ChemInform 07/2010; 66(11):1973-1979. DOI:10.1016/j.tet.2010.01.025
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ABSTRACT: Mammals produce three isoforms of nitric oxide synthase (NOS): neuronal NOS (nNOS), inducible NOS (iNOS) and endothelial NOS (eNOS). The overproduction of NO by nNOS is associated with a number of neurodegenerative disorders; therefore, a desirable therapeutic goal is the design of drugs that target nNOS but not the other isoforms. Crystallography, coupled with computational approaches and medicinal chemistry, has played a critical role in developing highly selective nNOS inhibitors that exhibit exceptional neuroprotective properties. For historic reasons, crystallography has focused on rat nNOS and bovine eNOS because these were available in high quality; thus, their structures have been used in structure-activity-relationship studies. Although these constitutive NOSs share more than 90% sequence identity across mammalian species for each NOS isoform, inhibitor-binding studies revealed that subtle differences near the heme active site in the same NOS isoform across species still impact enzyme-inhibitor interactions. Therefore, structures of the human constitutive NOSs are indispensible. Here, the first structure of human neuronal NOS at 2.03 Å resolution is reported and a different crystal form of human endothelial NOS is reported at 1.73 Å resolution.Acta Crystallographica Section D Biological Crystallography 10/2014; 70(Pt 10):2667-74. DOI:10.1107/S1399004714017064 · 7.23 Impact Factor
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ABSTRACT: Overproduction of NO by nNOS is implicated in the pathogenesis of diverse neuronal disorders. Since NO signaling is involved in diverse physiological functions, selective inhibition of nNOS over other isoforms is essential to minimize side effects. A series of α-amino functionalized aminopyridine derivatives (3 - 8) were designed to probe the structure-activity relationship between ligand, heme propionate, and H4B. Compound 8R was identified as the most potent and selective molecule of this study, exhibiting a Ki of 24 nM for nNOS, with 273-fold and 2822-fold selectivity against iNOS and eNOS, respectively. Although crystal structures of 8R complexed with nNOS and eNOS revealed a similar binding mode, the selectivity stems from the distinct electrostatic environments in two isoforms that result in much lower inhibitor binding free energy in nNOS than in eNOS. These findings provide a basis for further development of simple, but even more selective and potent, nNOS inhibitors.Journal of Medicinal Chemistry 04/2014; 57(10). DOI:10.1021/jm5004182 · 5.48 Impact Factor