Light adaptation of bacteriorhodopsin in the presence of valinomycin and potassium. pH-dependence

✍ Scribed by Dominique Massotte; Francois Boucher; Jacques Aghion

• Publisher: Springer
• Year: 1988
• Tongue: English
• Weight: 388 KB
• Volume: 18
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00034835

✦ Synopsis

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.