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The localization of Terbium (Tb3+) cations binding to deionized bacteriorhodopsin (bR) has been studied by using spectroscopic methods. It was found that adding
Tb3+ cations to deionized bR affects the fluorescence lifetimes of tryptophan (Trp) in bR, the wavelength of fluorescence peak
shifts “blue” and the peak value of fluorescence decreases. It was also found that adding one Tb3+ cation to deionized bR can restore the purple state from its blue state obviously. The measurements of absorbance, fluorescence
and lifetime of fluorescence also show that when more than three Tb3+ cations are added, no further changes can be found. It is suggested that one Tb3+ specific binding site for the color-controlling is located on the exterior of the bR trimer structure to negatively charged
lipids near Trp-10 and Trp-12. Three Tb3+ cations binding per bR is needed for the regenerated bR. 相似文献
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细菌视紫红质(bacteriorhodopsin,用bR表示)是嗜盐菌(halobacterium halobium)紫膜中发现的唯一蛋白质,由于具有独特质子泵和光色互变功能以及高稳定性,而成为理想的生物材料。在光照下,它产生典型的微分脉冲电信号[1],而且响应快,这对于它在信息存储、仿视觉系统等应用方面有极大的应用前景。 相似文献
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应用重组PCR的方法,直接从盐沼盐杆菌(Halobactrium salinarium)S9的基因组DNA上扩增到了编码细菌视紫红质(bacteriorhodopsin)的基因——bop基因及其启动子部分(1196bp),并将其克隆到表达载体pXLNovR后,在宿主菌株中得到了表达.测序结果表明,扩增得到的片段与NCBI数据库中的bop基因及启动子的序列完全相同,且其表达产物的分子量与野生型BR蛋白的分子量一致,并且在568nm处表现出BR蛋白特征吸收峰.本方法与其他方法(如逆转录PCR,建立基因文库后从中调取等方法)相比具有操作简便,成功率高的优点. 相似文献
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用重叠PCR的方法,定点突变细菌视紫红质(bacteriorhodopsin,BR),克隆到单突变体BRD96N和双突变体BRD38R/D96N的基因,同源转化盐沼盐杆菌(Halobacterium salinarium)L33(BR),表达突变蛋白BRD96N和BRD38R/D96N通过显微视频方法对突变BR的M态光致变色特性进行记录,BRD38R/D96N的M态寿命为5s,约为BRD96N(M态寿命为3s)的1.7倍.对突变体的激光共聚焦拉曼光谱测定发现,在BRD96N中,1170cm^-1下移到1171cm^-1,1258cm^-1上移到1255cm^-1,而BRD38R/D96N中1170cm^-1下移到1173cm^-1;1258cm^-1。上移到1252cm^-1,而且BRD38R/D96N与BRD96N相比,1186cm^-1处的峰明显增强.近紫外区圆二色谱显示,两种突变体近紫外区的正负带虽然没有太大差别,但288nm和290nm处的极峰却差别显著.所有这些研究结果表明,细菌视紫红质Asp38(D38)突变为Arg(R)可以延长其光循环后半程M态和N态的寿命. 相似文献
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在线偏振飞秒激光激发下, 菌紫质通过双光子光化学反应可以生成具有永久光致各向异性的蓝移产物F540态. 基于F540态的永久光致各向异性, 通过调控飞秒激光空间光场分布, 可以在菌紫质薄膜中实现永久光信息存储. 本文使用纯相位型空间光调制器调制飞秒激光光场, 在物镜焦平面上生成光学点阵图案, 可以将信息快速记录在菌紫质薄膜中. 同时, 通过改变入射激光偏振方向, 可以实现偏振复用光存储, 这在高密度光存储和数据加密领域具有潜在应用. 相似文献
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Anil Khanal Yan Pan Leonid S. Brown Lars Konermann 《Journal of mass spectrometry : JMS》2012,47(12):1620-1626
Kinetic folding experiments by pulsed hydrogen/deuterium exchange (HDX) mass spectrometry (MS) are a well‐established tool for water‐soluble proteins. To the best of our knowledge, the current study is the first that applies this approach to an integral membrane protein. The native state of bacteriorhodopsin (BR) comprises seven transmembrane helices and a covalently bound retinal cofactor. BR exposure to sodium dodecyl sulfate (SDS) induces partial unfolding and retinal loss. We employ a custom‐built three‐stage mixing device for pulsed‐HDX/MS investigations of BR refolding. The reaction is triggered by mixing SDS‐denatured protein with bicelles. After a variable folding time (10 ms to 24 h), the protein is exposed to excess D2O buffer under rapid exchange conditions. The HDX pulse is terminated by acid quenching after 24 ms. Subsequent off‐line analysis is performed by size exclusion chromatography and electrospray MS. These measurements yield the number of protected backbone N–H sites as a function of folding time, reflecting the recovery of secondary structure. Our results indicate that much of the BR secondary structure is formed quite late during the reaction, on a time scale of 10 s and beyond. It is hoped that in the future it will be possible to extend the pulsed‐HDX/MS approach employed here to membrane proteins other than BR. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Serge Crouzy Jerme Baudry Jeremy C. Smith Benoît Roux 《Journal of computational chemistry》1999,20(15):1644-1658
Accurate calculation of potential energy and free-energy profiles along reaction coordinates of biological processes such as enzymatic reactions or conformational changes is fundamental to the obtention of theoretical insight into protein function. We describe here the practical implementation of the Automatic Map Refinement Procedure (AMRP) and two-dimensional Weighted Histogram Analysis Method (WHAM) for efficient computation of adiabatic potential energy and free-energy maps, respectively. Methods for efficiently sampling configuration space with high-energy barriers and for removing hysteresis in the case of periodic reaction coordinates are presented. The application of these techniques to the isomerization of the C13C14 and C15N16 bonds in the retinal of bacteriorhodopsin is described. In dark-adapted bacteriorhodopsin (bR), the retinal moiety exists in two conformers, all-trans and (13,15)cis, with the latter making ≃67% of the population. This experimental free energy difference is reproduced here to within kBT. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1644–1658, 1999 相似文献