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Arg‐72 of pharaonis Phoborhodopsin (Sensory Rhodopsin II) is Important for the Maintenance of the Protein Structure in the Solubilized State ¶
Author(s) -
Ikeura Yukako,
Shimono Kazumi,
Iwamoto Masayuki,
Sudo Yuki,
Kamo Naoki
Publication year - 2003
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2003)0770096aoppsr2.0.co2
Subject(s) - rhodopsin , solubilization , sensory system , chemistry , biophysics , biochemistry , biology , neuroscience , retinal
In bacteriorhodopsin (bR), Arg‐82 bR has been proven to be a very important residue for functional role of this light‐driven proton pump. The arginine residue at this position is a super‐conserved residue among archaeal rhodopsins. pharaonis phoborhodopsin ( p pR; or called as “ pharaonis sensory rhodopsin II”) has its absorption maximum at 498 nm and acts as a sensor in the membrane of Natronobacterium pharaonis , mediating the negative phototaxis from the light of wavelength shorter than 520 nm. To investigate the role of the arginine residue (Arg‐72 p pR ) of p pR corresponding to Arg‐82 bR , mutants whose Arg‐72 p pR was replaced by alanine (R72A), lysine (R72K), glutamine (R72Q) and serine (R72S) were prepared. These mutants were unstable in low concentrations of NaCl and lost their color gradually when the proteins were solubilized with 0.1% n ‐dodecyl‐β‐ D ‐maltoside. The order of instability was R72S > R72A > R72K > R72Q > the wild type. The rates of denaturation were reduced in a solution of high concentrations of monovalent anions.