Structural highlights
Function[NOS3_BOVIN] Produces nitric oxide (NO) which is implicated in vascular smooth muscle relaxation through a cGMP-mediated signal transduction pathway. NO mediates vascular endothelial growth factor (VEGF)-induced angiogenesis in coronary vessels and promotes blood clotting through the activation of platelets. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPathological nitric oxide (NO) generation in sepsis, inflammation, and stroke may be therapeutically controlled by inhibiting NO synthases (NOS). Here we targeted the (6R)-5,6,7,8-tetrahydro-l-biopterin (H(4)Bip)-binding site of NOS, which, upon cofactor binding, maximally increases enzyme activity and NO production from substrate l-arginine. The first generation of H(4)Bip-based NOS inhibitors employed a 4-amino pharmacophore of H(4)Bip analogous to antifolates such as methotrexate. We developed a novel series of 4-oxo-pteridine derivatives that were screened for inhibition against neuronal NOS (NOS-I) and a structure-activity relationship was determined. To understand the structural basis for pterin antagonism, selected derivatives were docked into the NOS pterin binding cavity. Using a reduced 4-oxo-pteridine scaffold, derivatives with certain modifications such as electron-rich aromatic phenyl or benzoyl groups at the 5- and 6-positions, were discovered to markedly inhibit NOS-I, possibly due to hydrophobic and electrostatic interactions with Phe(462) and Ser(104), respectively, within the pterin binding pocket. One of the most effective 4-oxo compounds and, for comparisons an active 4-amino derivative, were then co-crystallized with the endothelial NOS (NOS-III) oxygenase domain and this structure solved to confirm the hypothetical binding modes. Collectively, these findings suggest (i) that, unlike the antifolate principle, the 4-amino substituent is not essential for developing pterin-based NOS inhibitors and (ii), provide a steric and electrostatic basis for their rational design. Structural basis for pterin antagonism in nitric-oxide synthase. Development of novel 4-oxo-pteridine antagonists of (6R)-5,6,7,8-tetrahydrobiopterin.,Kotsonis P, Frohlich LG, Raman CS, Li H, Berg M, Gerwig R, Groehn V, Kang Y, Al-Masoudi N, Taghavi-Moghadam S, Mohr D, Munch U, Schnabel J, Martasek P, Masters BS, Strobel H, Poulos T, Matter H, Pfleiderer W, Schmidt HH J Biol Chem. 2001 Dec 28;276(52):49133-41. Epub 2001 Oct 5. PMID:11590164[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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