The effect of charged lipids on bacteriorhodopsin membrane reconstitution and its photochemical activities.
Bacteriorhodopsin (BR) was reconstituted into artificial lipid membrane containing various charged lipid compositions. The proton pumping activity of BR under flash and continuous illumination, proton permeability across membrane, as well as the decay kinetics of the photocycle intermediate M(412) were studied. The results showed that lipid charges would significantly affect the orientation of BR inserted into lipid membranes. In liposomes containing anionic lipids, BRs were more likely to take natural orientation as in living cells. In neutral or positively charged liposomes, most BRs were reversely assembled, assuming an inside out orientation. Moreover, the lipids charges also affect BR's M intermediate kinetics, especially the slow component in M intermediate decay. The half-life M(412s) increased significantly in BRs in liposomes containing cationic lipids, while decreased in those in anionic liposomes.
Wang
Zhen
Z
College of Life Science & Biotechnology, Shanghai Jiaotong University, Shanghai 200240, China.
Bai
Jing
J
Xu
Yuhong
Y
D001436:Bacteriorhodopsins / Q000737:chemistry*; D004583:Electrons; D007700:Kinetics; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008564:Membrane Potentials; D010539:Permeability; D010777:Photochemistry; D011522:Protons
D008055:Lipids; D008081:Liposomes; D011522:Protons; D001436:Bacteriorhodopsins