2004年6月
Transient movement of helix F revealed by photo-induced inactivation by reaction of a bulky SH-reagent to cysteine-introduced pharaonis phoborhodopsin (sensory rhodopsin II)
Photochemical and Photobiological Sciences
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- 巻
- 3
- 号
- 6
- 開始ページ
- 537
- 終了ページ
- 542
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1039/b315454h
Pharaonis phoborhodopsin (ppR) is a photosensor of negative phototaxis in Natronomonas (Natronobacterium) pharaonis, an alkalophilic halophile. This protein has seven transmembrane helices into which a chromophore, all-trans retinal, binds to a specific lysine residue (located in helix G) via a protonated Schiff base. Various mutants were engineered to have a single cysteine in the F-helix. In the presence of a bulky fluorescent SH-reagent, MIANS, (2-(4′-maleimidylanilino)naphthalene-6-sulfonic acid, illumination decreased the photoreactivity or flash-yield (absorbance deflection immediately after the flash) of the L163C ppR mutant (in which Leu-163 was replaced with Cys) without changing the photocycling rate. The fluorescence of the isolated protein increased with increasing illumination. These observations suggest that during photocycling, the space around Cys-163 in the F-helix might open, permitting reaction with the relatively large molecule. This reaction occurred only at the M-state and not at the O-state. The implications are discussed. © The Royal Society of Chemistry and Owner Societies 2004.
- ID情報
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- DOI : 10.1039/b315454h
- ISSN : 1474-905X
- PubMed ID : 15170482
- SCOPUS ID : 3242746807