• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta crystallographica.Section D. Biological crystallography >X-ray structure of the metcyano form of dehaloperoxidase from Amphitrite ornata: evidence for photoreductive dissociation of the iron-cyanide bond.
【24h】

X-ray structure of the metcyano form of dehaloperoxidase from Amphitrite ornata: evidence for photoreductive dissociation of the iron-cyanide bond.

机译：x射线metcyano形式的结构dehaloperoxidase从安菲特律特这种:证据的photoreductive离解iron-cyanide债券。

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

X-ray crystal structures of the metcyano form of dehaloperoxidase-hemoglobin (DHP A) from Amphitrite ornata (DHPCN) and the C73S mutant of DHP A (C73SCN) were determined using synchrotron radiation in order to further investigate the geometry of diatomic ligands coordinated to the heme iron. The DHPCN structure was also determined using a rotating-anode source. The structures show evidence of photoreduction of the iron accompanied by dissociation of bound cyanide ion (CN(-)) that depend on the intensity of the X-ray radiation and the exposure time. The electron density is consistent with diatomic molecules located in two sites in the distal pocket of DHPCN. However, the identities of the diatomic ligands at these two sites are not uniquely determined by the electron-density map. Consequently, density functional theory calculations were conducted in order to determine whether the bond lengths, angles and dissociation energies are consistent with bound CN(-) or O(2) in the iron-bound site. In addition, molecular-dynamics simulations were carried out in order to determine whether the dynamics are consistent with trapped CN(-) or O(2) in the second site of the distal pocket. Based on these calculations and comparison with a previously determined X-ray crystal structure of the C73S-O(2) form of DHP [de Serrano et al. (2007), Acta Cryst. D63, 1094-1101], it is concluded that CN(-) is gradually replaced by O(2) as crystalline DHP is photoreduced at 100 K. The ease of photoreduction of DHP A is consistent with the reduction potential, but suggests an alternative activation mechanism for DHP A compared with other peroxidases, which typically have reduction potentials that are 0.5 V more negative. The lability of CN(-) at 100 K suggests that the distal pocket of DHP A has greater flexibility than most other hemoglobins.
机译：x射线metcyano形成的晶体结构dehaloperoxidase-hemoglobin(设计马力)安菲特律特这种(DHPCN)和C73S突变使用同步加速器设计马力(C73SCN)测定为了进一步研究辐射几何的双原子配体协调血红素铁。决定使用一个旋转阳极的来源。结构显示的光致还原作用的证据铁伴随着离解的氰化物离子(CN(-))依赖的强度x射线辐射和曝光时间。电子密度与双原子是一致的远端分子位于两个站点DHPCN的口袋里。双原子配体在这两个网站都不是独特的由电子密度图。因此,密度泛函理论进行了计算,以确定无论是债券长度、角度和离解能量是符合绑定CN(-)或O (2)铁箍的网站。分子动力学模拟进行为了确定动力学符合困CN(-)或(2)第二远的口袋里。与先前的计算和比较x射线晶体结构的决定Acta结晶。CN(-)逐渐取代了O (2)水晶设计马力photoreduced在100 K。易于设计马力的光致还原作用是一致的的还原电位,但提出了一个选择激活的机制设计马力与其他氧化物酶相比,通常有潜力减少0.5 V更多负的。的远端口袋设计马力更大灵活性比大多数其他血红蛋白。

著录项

相似文献

  • 中文文献
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