Characterization of cyanobacteriochrome TePixJ from a thermophilic cyanobacterium Thermosynechococcus elongatus strain BP-1
Characterization of cyanobacteriochrome TePixJ from a thermophilic cyanobacterium Thermosynechococcus elongatus strain BP-1
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DOI：
10.1093/pcp/pcj095
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发表时间：
2006-09-01
影响因子：
4.9
通讯作者：
Ikeuchi, Masahiko
中科院分区：
文献类型：
--
作者：
Ishizuka, Takami;Shimada, Takashi;Ikeuchi, Masahiko
一个假定的光感受器基因，TepixJ，嗜热蓝细菌是同源的SypixJ 1介导积极的趋光性在单细胞能动蓝细菌集胞藻属PCC 6803。TePixJ蛋白的假定发色团结合GAF结构域在集胞藻细胞中过表达为与多组氨酸标签（His-TePixJ_GAF）的融合物，并分离至均一。His-TePixJ_GAF的光可逆转化对于绿色光吸收形式（Pg形式）在531、341和266 nm处显示峰，并且对于蓝光吸收形式（Pb形式）在433和287 nm处显示峰。在77 K下，Pg形式在580 nm处发荧光，而Pb形式不发射任何荧光。胰蛋白酶的色肽的质谱分析表明，藻蓝胆素异构体结合保守的半胱氨酸在环A通过硫醚键。它是建立，TePixJ和SyPixJ 1是新的光感受器在蓝藻（'蓝细菌色素'）是相似的，但不同的光敏色素和细菌光敏色素。
A putative photoreceptor gene, TepixJ, of a thermophilic cyanobacterium is homologous to SypixJ1 that mediates positive phototaxis in the unicellular motile cyanobacterium Synechocystis sp. PCC 6803. The putative chromophore-binding GAF domain of TePixJ protein was overexpressed as a fusion with a polyhistidine tag (His-TePixJ_GAF) in Synechocystis cells and isolated to homogeneity. The photoreversible conversion of His-TePixJ_GAF showed peaks at 531, 341 and 266 nm for the green light-absorbing form (Pg form), and peaks at 433 and 287 nm for the blue light-absorbing form (Pb form). At 77K, the Pg form fluoresced at 580 nm, while the Pb form did not emit any fluorescence. Mass spectrometry of the tryptic chromopeptide demonstrated that a phycocyanobilin isomer binds to the conserved cysteine at ring A via a thioether bond. It is established that TePixJ and SyPixJ1 are novel photoreceptors in cyanobacteria ('cyanobacteriochromes') that are similar, but distinct from the phytochromes and bacteriophytochromes.