• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Pulsed ENDOR determination of the arginine location in the ferrous-NO form of neuronal NOS
【24h】

Pulsed ENDOR determination of the arginine location in the ferrous-NO form of neuronal NOS

机译：脉冲ENDOR测定神经元NOS的亚铁NO形式中的精氨酸位置

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Mammalian nitric oxide synthases (NOSs) are enzymes responsible for oxidation of l-arginine (l-Arg) to nitric oxide (NO). Mechanisms of reactions at the catalytic heme site are not well understood, and it is of current interest to study structures of the heme species that activates O _2 and transforms the substrate. The NOS ferrous-NO complex is a close mimic of the obligatory ferric (hydro)peroxo intermediate in NOS catalysis. In this work, pulsed electron-nuclear double resonance (ENDOR) was used to probe the position of the l-Arg substrate at the NO ~?-coordinated ferrous heme center(s) in the oxygenase domain of rat neuronal NOS (nNOS). The analysis of ~2H and ~(15)N ENDOR spectra of samples containing d _7- or guanidino- ~(15)N _2 labeled l-Arg has resulted in distance estimates for the nearby guanidino nitrogen and the nearby proton (deuteron) at C _δ. The l-Arg position was found to be noticeably different from that in the X-ray crystal structure of nNOS ferrous-NO complex [Li et al. J. Biol. Inorg. Chem.2006, 11, 753-768], with the nearby guanidino nitrogen being ～0.5 ? closer to, and the nearby H _δ about 1 ? further from, the NO ligand than in the X-ray structure. The difference might be related to the structural constraints imposed on the protein by the crystal. Importantly, in spite of its closer position, the guanidino nitrogen does not form a hydrogen bond with the NO ligand, as evidenced by the absence of significant isotropic hfi constant for N _(g1). This is consistent with the previous reports that it is not the l-Arg substrate itself that would most likely serve as a direct proton donor to the diatomic ligands (NO and O _2) bound to the heme.
机译：哺乳动物一氧化氮合酶（NOS）是负责将1-精氨酸（1-Arg）氧化为一氧化氮（NO）的酶。催化血红素位点的反应机理尚未得到很好的理解，目前研究激活O _2并转化底物的血红素种类的结构是当前感兴趣的。 NOS亚铁-NO络合物非常类似于NOS催化中的强制性铁（氢）过氧中间体。在这项工作中，脉冲电子核双共振（ENDOR）用于探测大鼠神经元NOS（nNOS）的加氧酶结构域中由NO〜α配位的亚铁血红素中心的l-Arg底物的位置。含有d _7-或胍基-〜（15）N _2标记为l-Arg的样品的〜2H和〜（15）N ENDOR光谱分析已得出附近胍基氮和附近质子（氘）的距离估计C_δ。发现1-Arg位置与nNOS亚铁-NO配合物的X射线晶体结构中的位置明显不同[Li等人，J.Biol.Chem。，1992]。 J.Biol。 Inorg。 Chem.2006，11，11，753-768]，附近的胍基氮为〜0.5？接近，附近的H_δ约为1？与X射线结构相比，NO配体更远。差异可能与晶体对蛋白质施加的结构限制有关。重要的是，胍基氮尽管位置较近，但仍未与NO配体形成氢键，这由N_（g1）的不明显的各向同性hfi常数所证明。这与先前的报道一致，即不是l-Arg底物本身最有可能充当与血红素结合的双原子配体（NO和O _2）的直接质子供体。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号