Merocyanines as Extremely Bathochromically Absorbing Chromophores in the Halobacterial Membrane Protein Bacteriorhodopsin

摘要

The binding of ligands to proteins can lead to significant changes in their physical and chemical properties. This is particularly apparent for photoisomerizable chromoproteins. for example the membrane protein bacteriorhodopsin (BR) of the halophilicarchaebacterium Halobacterium salinurium, which contains retinal (1. see Scheme 1). Upon absorption of light, BR transports protons by a cyclic reaction sequence (the photocycle of BR lasts about 10 ms) into the outer medium, allowing the energy thus stored to be employed for further metabolic processes.