1niw

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spinqualitylabelsall models 1niw, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of endothelial nitric oxide synthase peptide bound to calmodulin

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

The enzyme nitric oxide synthase (NOS) is exquisitely regulated in vivo by, the Ca(2+) sensor protein calmodulin (CaM) to control production of NO, a, key signaling molecule and cytotoxin. The differential activation of NOS, isozymes by CaM has remained enigmatic, despite extensive research. Here, the crystallographic structure of Ca(2+)-loaded CaM bound to a 20 residue, peptide comprising the endothelial NOS (eNOS) CaM-binding region, establishes their individual conformations and intermolecular, interactions, and suggests the basis for isozyme-specific differences. The, alpha-helical eNOS peptide binds in an antiparallel orientation to CaM, through extensive hydrophobic interactions. Unique NOS interactions occur, with: (i). the CaM flexible central linker, explaining its importance in, NOS activation; and (ii). the CaM C-terminus, explaining the NOS-specific, requirement for a bulky, hydrophobic residue at position 144. This binding, mode expands mechanisms for CaM-mediated activation, explains eNOS, deactivation by Thr495 phosphorylation, and implicates specific, hydrophobic residues in the Ca(2+) independence of inducible NOS.

Disease

Known diseases associated with this structure: Alzheimer disease, late-onset, susceptibility to OMIM:[163729], Coronary spasms, susceptibility to OMIM:[163729], Hypertension, pregnancy-induced OMIM:[163729], Hypertension, susceptibility to OMIM:[163729], Ischemic stroke, susceptibility to OMIM:[163729], Placental abruption OMIM:[163729]

About this Structure

1NIW is a Protein complex structure of sequences from Rattus norvegicus 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 endothelial nitric oxide synthase binding to calmodulin., Aoyagi M, Arvai AS, Tainer JA, Getzoff ED, EMBO J. 2003 Feb 17;22(4):766-75. PMID:12574113

Page seeded by OCA on Fri Feb 15 16:29:10 2008