title: Light adaptation of bacteriorhodopsin in the presence of valinomycin and potassium. pH-dependence.
abstract: In the presence of valinomycin and K(+), bacteriorhodopsin undergoes (i) a decrease of its maximum absorbance, (ii) a blue shift of the maximum wavelength of both the light and the dark adapted forms. However (iii) a normal light adaptation is maintained and (iv) the retinal-retinal interactions are not perturbed. The role of valinomycin as a K(+)-carrier allowing a H(+)-K(+) competition as well as the stabilization of the deprotonated Schiff-base (linking retinal to the apo-opsin) is shown and discussed.
authors.affiliation: Laboratoire de Biochimie, Département de Botanique (B22), Université de Liège, B-4000, Liège, Belgique.
authors.forename: D
authors.initials: D
authors.lastname: Massotte
authors.forename: F
authors.initials: F
authors.lastname: Boucher
authors.forename: J
authors.initials: J
authors.lastname: Aghion