Crystal structures of the Synechocystis photoreceptor Slr1694 reveal distinct structural states related to signaling
Crystal structures of the Synechocystis photoreceptor Slr1694 reveal distinct structural states related to signaling
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DOI：
10.1021/bi061435n
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发表时间：
2006-10-24
期刊：
影响因子：
2.9
通讯作者：
Bauer, Carl
中科院分区：
文献类型：
--
作者：
Yuan, Hua;Anderson, Spencer;Bauer, Carl
集胞藻BLUF趋光性光感受器Slr 1694的晶体结构以两种晶体形式确定，在1.8埃分辨率下的单斜晶形式和在2.1埃分辨率下的斜方晶形式。在这两种形式中，感光体由两个面对面堆叠的五聚体环组成。这些晶体形式的两个不对称单元中的20个总亚基显示出三种不同的三级结构，其在第五β链的长度和Trp91（FMN发色团附近的保守Trp残基）的取向上不同。对溶液中Slr 1694的荧光光谱分析与Trp91从暗态的疏水环境到光激发态的更亲水环境的运动一致。突变分析表明，运动的Trp91是依赖于与附近的Met的疏水性色氨酸结合口袋的占用。这些不同的三级结构可能与光谱的蓝色区域中的吸收变化有关。
Crystal structures of the Synechocystis BLUF phototaxis photoreceptor Slr1694 have been determined in two crystal forms, a monoclinic form at 1.8 angstrom resolution and an orthorhombic form at 2.1 angstrom resolution. In both forms, the photoreceptor is comprised of two pentamer rings stacked face to face. Twenty total subunits in the two asymmetric units of these crystal forms display three distinct tertiary structures that differ in the length of the fifth beta-strand and in the orientation of Trp91, a conserved Trp residue near the FMN chromophore. Fluorescence spectroscopic analysis on Slr1694 in solution is consistent with motion of Trp91 from a hydrophobic environment in the dark state to a more hydrophilic environment in the light-excited state. Mutational analysis indicates that movement of Trp91 is dependent on the occupancy of the hydrophobic Trp binding pocket with a nearby Met. These different tertiary structures may be associated with absorption changes in the blue region of the spectrum.