Sessa W C, Harrison J K, Barber C M, Zeng D, Durieux M E, D'Angelo D D, Lynch K R, Peach M J
Department of Pharmacology, University of Virginia School of Medicine, Charlottesville 22908.
J Biol Chem. 1992 Aug 5;267(22):15274-6.
Endothelium-derived relaxing factor (EDRF), identified as nitric oxide (NO), is derived from a guanidino nitrogen of L-arginine via its metabolism by nitric oxide synthase (NOS). Herein, we report the molecular cloning of a cDNA encoding the constitutive calcium-calmodulin (Ca2+/CaM)-regulated nitric oxide synthase (ECNOS). A full-length ECNOS clone was isolated by screening a bovine aortic endothelial cell cDNA library using a fragment of rat brain NOS (bNOS) cDNA. This cDNA has an open reading frame of 3615 nucleotides encoding a 1205-amino acid protein. Membranes prepared from COS cells transfected with the ECNOS cDNA demonstrated NADPH- and Ca2+/CaM- dependent conversion of L-, but not D-, arginine to NO and citrulline that was inhibited by NG-nitro-L-arginine methyl ester. Comparison of the deduced amino acid sequence of ECNOS to the bNOS and macrophage NOS (Mac-NOS) sequences revealed 57 and 50% identity, respectively. In addition, ECNOS contains a unique N-myristylation consensus sequence (not shared by bNOS or Mac-NOS) that may explain its membrane localization.
内皮源性舒张因子（EDRF），即一氧化氮（NO），是由一氧化氮合酶（NOS）通过L-精氨酸的胍基氮代谢产生的。在此，我们报告了编码组成型钙调蛋白（Ca2+/CaM）调节型一氧化氮合酶（ECNOS）的cDNA的分子克隆。通过使用大鼠脑NOS（bNOS）cDNA片段筛选牛主动脉内皮细胞cDNA文库，分离出全长ECNOS克隆。该cDNA具有3615个核苷酸的开放阅读框，编码一个1205个氨基酸的蛋白质。用ECNOS cDNA转染的COS细胞制备的膜显示，L-精氨酸（而非D-精氨酸）在NADPH和Ca2+/CaM依赖的情况下转化为NO和瓜氨酸，且该转化受到NG-硝基-L-精氨酸甲酯的抑制。将ECNOS推导的氨基酸序列与bNOS和巨噬细胞NOS（Mac-NOS）序列进行比较，分别显示出57%和50%的同一性。此外，ECNOS含有一个独特的N-肉豆蔻酰化共有序列（bNOS或Mac-NOS不共享），这可能解释了其膜定位。
