1dmk: Difference between revisions

[[Image:1dmk.gif|left|200px]]<br /><applet load="1dmk" size="350" color="white" frame="true" align="right" spinBox="true"  

Pathological 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.

1DMK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=ACT:'>ACT</scene>, <scene name='pdbligand=CAC:'>CAC</scene>, <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=AP6:'>AP6</scene> and <scene name='pdbligand=ITU:'>ITU</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Nitric-oxide_synthase Nitric-oxide synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.13.39 1.14.13.39] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DMK OCA].  

[[Category: Frohlich, L G.]]

[[Category: Masters, B S.]]

[[Category: Raman, C S.]]

[[Category: Schmidt, H H.]]

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