Salinibacter sensory rhodopsin -: Sensory rhodopsin I-like protein from a eubacterium
Salinibacter sensory rhodopsin -: Sensory rhodopsin I-like protein from a eubacterium
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DOI：
10.1074/jbc.m802990200
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发表时间：
2008-08-29
影响因子：
4.8
通讯作者：
Sudo, Yuki
中科院分区：
文献类型：
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作者：
Kitajima-Ihara, Tomomi;Furutani, Yuji;Sudo, Yuki
盐杆菌感觉视紫红质 I (HsSRI) 是盐古菌中调节负趋光性和正趋光性的双重受体，通过蛋白质与其传感器、盐细菌传感器蛋白 I (HtrI) 相互作用的变化来传输光信号。 Haloarchaea 还具有另一种传感器色素，感觉视紫红质 II (SRII)，其功能是调节负趋光性的受体。与 HsSRI 相比，SRII 的信号传递机制得到了很好的表征，因为来自 Natronomonus pharaonis (NpSRII) 的 SRII 比 HsSRI 和 HsSRII 稳定得多，特别是在稀盐溶液中，并且对洗涤剂具有更强的抵抗力。从红盐杆菌的基因组序列中鉴定出两个编码 SRI 同源物的基因。这些序列与 HsSRI 关系较远（相似度为 40%），并且包含大部分被确定为其功能所必需的氨基酸残基。为了确定这些基因是否编码功能蛋白，我们在大肠杆菌中克隆并表达了它们。其中之一（SrSRI）作为以全反式视黄醛作为发色团的重组蛋白得到良好表达。 UV-Vis、低温UVVis、pH滴定和闪光光解实验表明SrSRI的光化学性质与HsSRI相似。除了表达系统之外，SrSRI 的高稳定性使得制备大量蛋白质成为可能，并能够研究突变蛋白，这将允许新的方法来研究 SRI-HtrI 的光信号传导过程。
Halobacterium salinarum sensory rhodopsin I ( HsSRI), a dual receptor regulating both negative and positive phototaxis in haloarchaea, transmits light signals through changes in proteinprotein interactions with its transducer, halobacterial transducer protein I ( HtrI). Haloarchaea also have another sensor pigment, sensory rhodopsin II ( SRII), which functions as a receptor regulating negative phototaxis. Compared with HsSRI, the signal relay mechanism of SRII is well characterized because SRII from Natronomonus pharaonis ( NpSRII) is much more stable than HsSRI and HsSRII, especially in dilute salt solutions and is much more resistant to detergents. Two genes encoding SRI homologs were identified from the genome sequence of the eubacterium Salinibacter ruber. Those sequences are distantly related to HsSRI (similar to 40% identity) and contain most of the amino acid residues identified as necessary for its function. To determine whether those genes encode functional protein( s), we cloned and expressed them in Escherichia coli. One of them ( SrSRI) was expressed well as a recombinant protein having alltrans retinal as a chromophore. UV- Vis, low- temperature UVVis, pH- titration, and flash photolysis experiments revealed that the photochemical properties of SrSRI are similar to those of HsSRI. In addition to the expression system, the high stability of SrSRI makes it possible to prepare large amounts of protein and enables studies of mutant proteins that will allow new approaches to investigate the photosignaling process of SRI- HtrI.