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Inhibition of the M1→M2 (M closed →M open ) transition in the D96N mutant photocycle and its relation to the corresponding transition in wild‐type bacteriorhodopsin
Author(s) -
Radionov Alexey N,
Kaulen Andrey D
Publication year - 1997
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(97)00474-2
Subject(s) - chemistry , mutant , bacteriorhodopsin , wild type , crystallography , ion , stereochemistry , biochemistry , organic chemistry , membrane , gene
Glutaraldehyde, lutetium ions and glycerol inhibit the blue shift of the difference spectra maximum of the M intermediate in the D96N mutant. The M formed has a spectrum indistinguishable from the M intermediate in wild‐type bacteriorhodopsin. It has been concluded that the M open form previously described by us is identical to the M2 and M n intermediates postulated by Zimanyi et al. ( Photochem. Photobiol . (1992) 56, 1049–1055) and Sasaki et al. ( J. Biol. Chem . (1992) 267, 20782–20786), respectively. It is supposed that its formation is accompanied by the appearance of the cytoplasmic proton half‐channel. M open in the wild‐type protein is present in a very low amount due to the shift of the M closed ↔M open equilibrium towards the M closed . The inhibitors used do not prevent the multiphase pattern of the M formation in either mutant or wild‐type proteins.