His166 Is the Schiff Base Proton Acceptor in Attractant Phototaxis Receptor Sensory Rhodopsin I
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چکیده
منابع مشابه
His166 Is the Schiff Base Proton Acceptor in Attractant Phototaxis Receptor Sensory Rhodopsin I
Photoactivation of attractant phototaxis receptor sensory rhodopsin I (SRI) in Halobacterium salinarum entails transfer of a proton from the retinylidene chromophore's Schiff base (SB) to an unidentified acceptor residue on the cytoplasmic half-channel, in sharp contrast to other microbial rhodopsins, including the closely related repellent phototaxis receptor SRII and the outward proton pump b...
متن کاملA Schiff base connectivity switch in sensory rhodopsin signaling.
Sensory rhodopsin I (SRI) in Halobacterium salinarum acts as a receptor for single-quantum attractant and two-quantum repellent phototaxis, transmitting light stimuli via its bound transducer HtrI. Signal-inverting mutations in the SRI-HtrI complex reverse the single-quantum response from attractant to repellent. Fast intramolecular charge movements reported here reveal that the unphotolyzed SR...
متن کاملAttractant and Repellent Signaling Conformers of Sensory Rhodopsin−Transducer Complexes†
Attractant and repellent signaling conformers of the dual-signaling phototaxis receptor sensory rhodopsin I and its transducer subunit (SRI-HtrI) have recently been distinguished experimentally by the opposite connection of their retinylidene protonated Schiff bases to the outwardly located periplasmic side and inwardly located cytoplasmic side. Here we show that the pK(a) of the outwardly loca...
متن کاملAspartic acid 85 in bacteriorhodopsin functions both as proton acceptor and negative counterion to the Schiff base.
In bacteriorhodopsin Asp85 has been proposed to function both as a negative counterion to the Schiff base and as proton acceptor in the early stages of the photocycle. To test this proposal further, we have replaced Asp85 by His. The rationale for this replacement is that although His can function as a proton acceptor, it cannot provide a negative charge at residue 85 to serve as a counterion t...
متن کاملOpposite displacement of helix F in attractant and repellent signaling by sensory rhodopsin-Htr complexes.
Two forms of the phototaxis receptor sensory rhodopsin I distinguished by differences in its photoactive site have been shown to be directly correlated with attractant and repellent signaling by the dual-signaling protein. In prior studies, differences in the photoactive site defined the two forms, namely the direction of light-induced proton transfer from the chromophore and the pK(a) of an As...
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ژورنال
عنوان ژورنال: Biochemistry
سال: 2014
ISSN: 0006-2960,1520-4995
DOI: 10.1021/bi500831n