TY - JOUR
T1 - Opening the Schiff base moiety of bacteriorhodopsin by mutation of the four extracellular Glu side chains
AU - Sanz, Carolina
AU - Lazarova, Tzvetana
AU - Sepulcre, Francesc
AU - González-Moreno, Rafael
AU - Bourdelande, José Luis
AU - Querol, Enric
AU - Padrós, Esteve
PY - 1999/7/30
Y1 - 1999/7/30
N2 - The quadruple bacteriorhodopsin (BR) mutant E9Q+E74Q+E194Q+E204Q shows a λ(max) of about 500 nm in water at neutral pH and a great influence of pH and salts on the visible absorption spectrum. Accessibility to the Schiff base is strongly increased, as detected by the rapid bleaching effect of hydroxylamine in the dark as well as in light. Both the proton release kinetics and the photocycle are altered, as indicated by a delayed proton release after proton uptake and changed M kinetics. Moreover, affinity of the color-controlling cation(s) is found to be decreased. We suggest that the four Glu side chains are essential elements of the extracellular structure of BR. Copyright (C) 1999 Federation of European Biochemical Societies.
AB - The quadruple bacteriorhodopsin (BR) mutant E9Q+E74Q+E194Q+E204Q shows a λ(max) of about 500 nm in water at neutral pH and a great influence of pH and salts on the visible absorption spectrum. Accessibility to the Schiff base is strongly increased, as detected by the rapid bleaching effect of hydroxylamine in the dark as well as in light. Both the proton release kinetics and the photocycle are altered, as indicated by a delayed proton release after proton uptake and changed M kinetics. Moreover, affinity of the color-controlling cation(s) is found to be decreased. We suggest that the four Glu side chains are essential elements of the extracellular structure of BR. Copyright (C) 1999 Federation of European Biochemical Societies.
KW - Bacteriorhodopsin
KW - E9Q+E74Q+E194Q+E204Q mutant
KW - Extracellular structure
KW - Hydroxylamine accessibility
U2 - 10.1016/S0014-5793(99)00950-3
DO - 10.1016/S0014-5793(99)00950-3
M3 - Article
VL - 456
SP - 191
EP - 195
IS - 1
ER -