Transient Dissociation of the Transducer Protein from Anabaena Sensory Rhodopsin Concomitant with Formation of the M State Produced upon Photoactivation

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• 作者：Masato Kondoh ; Keiichi Inoue ; Jun Sasaki ; John L. Spudich ; Masahide Terazima
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：August 31, 2011
• 年：2011
• 卷：133
• 期：34
• 页码：13406-13412
• 全文大小：826K
• 年卷期：v.133,no.34(August 31, 2011)
• ISSN：1520-5126

文摘

Anabaena sensory rhodopsin (ASR), a microbial rhodopsin in the cyanobacterium sp. PCC7120, has been suggested to regulate cell processes in a light-quality-dependent manner (color-discrimination) through interaction with a water-soluble transducer protein (Tr). However, light-dependent ASR鈥揟r interaction changes have yet to be demonstrated. We applied the transient grating (TG) method to investigate protein鈥損rotein interaction between ASR with Tr. The molecular diffusion component of the TG signal upon photostimulation of ASR_AT (ASR with an all-trans retinylidene chromophore) revealed that Tr dissociates from ASR upon formation of the M-intermediate and rebinds to ASR during the decay of M; that is, light induces transient dissociation of ASR and Tr during the photocycle. Further correlating the dissociation of the ASR鈥揟r pair with the M-intermediate, no transient dissociation was observed after the photoexcitation of the blue-shifted ASR_13C (ASR with 13-cis, 15-syn chromophore), which does not produce M. This distinction between ASR_AT and ASR_13C, the two isomeric forms in a color-sensitive equilibrium in ASR, provides a potential mechanism for color-sensitive signaling by ASR.