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Triton X‐100 can alter the temporal sequence of the light‐driven proton pump of archaerhodopsin 4
Author(s) -
Ming Ming,
Wang Yazhuo,
Wu Jia,
Ma Dewang,
Li Qingguo,
Ding Jiandong
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.11.035
Subject(s) - bacteriorhodopsin , proton , biophysics , chemistry , proton pump , halobacterium , halobacteriaceae , biochemistry , membrane , halobacterium salinarum , biology , physics , enzyme , atpase , quantum mechanics
We report that Triton X‐100 can alter the temporal sequence of the light‐induced proton uptake and release of archaerhodopsin 4 (AR4), a proton pumping protein in a species of Halobacteria from a Tibetan salt lake. Under physiological conditions, AR4 isolated from the bacterium exhibits a reversed temporal order of proton release and uptake compared to what is observed for bacteriorhodopsin (BR). However, in the presence of Triton X‐100 early proton release was observed in AR4 at neutral pH by us. Further, this temporal order for light‐driven proton release and uptake for AR4 was found to be recovered after the removal of Triton X‐100 by Biobeads. This phenomenon of detergent‐induced alteration of the order of proton release and uptake has not yet been reported in any other retinal‐containing membrane protein such as BR. Our findings indicate that the function of AR4 is influenced by its self‐assembled state, and meanwhile imply some subtle protein–lipid interactions or protein–protein interactions in adjusting the proton pumping behavior of AR4.