...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Reconstitution of Gloeobacter violaceus Rhodopsin with a Light-Harvesting Carotenoid Antenna
【24h】

Reconstitution of Gloeobacter violaceus Rhodopsin with a Light-Harvesting Carotenoid Antenna

机译：采光类胡萝卜素天线重建紫罗兰菌视紫红质

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

We show that salinixanthin, the light-harvesting carotenoid antenna of xanthorhodopsin, can benreconstituted into the retinal protein from Gloeobacter violaceus expressed in Escherichia coli. Reconstitutionnof gloeobacter rhodopsin with the carotenoid is accompanied by characteristic absorption changes and thenappearance of CD bands similar to those observed for xanthorhodopsin that indicate immobilization andntwist of the carotenoid in the binding site. As in xanthorhodopsin, the carotenoid functions as a light-nharvesting antenna. The excitation spectrum for retinal fluorescence emission shows that ca. 36% of thenenergy absorbed by the carotenoid is transferred to the retinal. From excitation anisotropy, we calculate thenangle between the two chromophores as being ca. 50u0001, similar to that in xanthorhodopsin. The results indicatenthat gloeobacter rhodopsin binds salinixanthin in a manner similar to that of xanthorhodopsin and suggestnthat it might bind a carotenoid also in vivo. In the crystallographic structure of xanthorhodopsin, thenconjugated chain of the carotenoid lies on the surface of helices E and F, and the 4-keto ring is immersed in thenprotein at van derWaals distance from the ionone ring of the retinal. The 4-keto ring is in the space occupiednby a tryptophan in bacteriorhodopsin, which is replaced by the smaller glycine in xanthorhodopsin andngloeobacter rhodopsin. Specific binding of the carotenoid and its light-harvesting function are eliminated by ansingle mutation of the gloeobacter protein that replaces this glycine with a tryptophan. This indicates that then4-keto ring is critically involved in carotenoid binding and suggests that a number of other recently identifiednretinal proteins, froma diverse group of organisms, could also contain carotenoid antenna since they carry thenhomologous glycine near the retinal.
机译：我们表明，盐嘌呤黄素，黄嘌呤视紫红质的集光类胡萝卜素天线，可以从大肠杆菌中表达的紫色紫球藻（Gloeobacter violaceus）的视网膜蛋白中重建。球形细菌视紫红质与类胡萝卜素的重建伴随有特征性的吸收变化，然后出现与黄原视紫红质相似的CD条带，表明类固醇在结合位点固定和扭曲。与黄原视紫红质一样，类胡萝卜素起着吸光天线的作用。视网膜荧光发射的激发光谱表明，约。类胡萝卜素吸收的能量的36％转移到视网膜。根据激发各向异性，我们计算出两个生色团之间的夹角为。 50u0001，类似于黄藻视紫红质。结果表明，细菌视紫红质以与黄藻视紫红质相似的方式结合红霉素黄嘌呤，并暗示其也可能在体内结合类胡萝卜素。在黄体视紫红质的晶体结构中，类胡萝卜素的共轭链位于螺旋E和F的表面上，然后将4-酮环浸入距视网膜紫罗兰酮环范德华（van derWaals）距离处的蛋白质中。 4-酮环位于细菌视紫红质中的一个色氨酸所占据的空间内，该空间被黄藻视紫红质和视紫红质细菌中的较小甘氨酸所取代。类胡萝卜素的特异性结合及其光捕获功能可通过将该甘氨酸替换为色氨酸的glooebacter蛋白的单突变来消除。这表明然后4-酮环与类胡萝卜素的结合至关重要，并表明来自不同生物体的许多其他近期鉴定的视网膜蛋白也可能含有类胡萝卜素触角，因为它们在视网膜附近携带同源的甘氨酸。

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