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Distortion of the L→M transition in the photocycle of the bacteriorhodopsin mutant D96N: a time‐resolved step‐scan FTIR investigation
Author(s) -
Rödig C,
Siebert F
Publication year - 1999
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/s0014-5793(99)00088-5
Subject(s) - bacteriorhodopsin , distortion (music) , fourier transform infrared spectroscopy , mutant , chemistry , analytical chemistry (journal) , biophysics , nuclear magnetic resonance , photochemistry , materials science , optics , physics , biology , optoelectronics , biochemistry , membrane , chromatography , gene , amplifier , cmos
The D96N mutant of bacteriorhodopsin has often been taken as a model system to study the M intermediate of the wild type photocycle due to the long life time of the corresponding intermediate of the mutant. Using time‐resolved step‐scan FTIR spectroscopy in combination with a sample changing wheel we investigated the photocycle of the mutant with microsecond time resolution. Already after several microseconds an intermediate similar to the M N state is observed, which contrasts with the M state of the wild type protein. At reduced hydration M and N intermediates similar to those of wild type BR can be detected. These results have a bearing on the interpretation of the photocycle of this mutant. A mechanism is suggested for the fast rise of M N which provides some insight into the molecular events involved in triggering the opening of the cytosolic channel also of the wild type protein.