Article

The effect of lipid environment in purple membrane on bacteriorhodopsin

Institute of Biophysics Academia Sinica, Beijing, China.
Journal of Photochemistry and Photobiology B Biology (Impact Factor: 2.8). 12/2000; 58(2-3):163-9. DOI: 10.1016/S1011-1344(00)00125-1
Source: PubMed

ABSTRACT The decay rate of the Bacteriorhodopsin (BR) photocycle intermediate M412 and proton, the proton pump efficiency (H+/M412), the ratios of M412 to other intermediates and the rotational correlation time (tauc) in purple membrane (PM) fragments treated by the zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) with different concentrations were studied. The results show that: (1) The largest effect of CHAPS on M412 decay rate and proton decay rate of BR, tauc of PM and the ratios of M412 to other intermediates in BR photocycle is in the range of its critical micelle concentration (CMC). This indicates that changes of the ratios of M412 to other intermediates, tauc, M412 decay and proton decay occur and are due to the variation of the lipid environment. (2) The dependency of proton yield on CHAPS concentrations is basically consistent with that of M412s%. This indicates the relation between proton pumping function and M412. These studies show the importance of maintaining a native environment.

0 Followers
 · 
64 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Archaerhodopsin 4 (AR4), a new member of the microbial rhodopsin family, is isolated from Halobacterium species xz515 in a Tibetan salt lake. AR4 functions as a proton pump similar to bacteriorhodopsin (BR) but with an opposite temporal order of proton uptake and release at neutral pH. However, further studies to elucidate the mechanism of the proton pump and photocycle of AR4 have been inhibited due to the difficulty of establishing a suitable system in which to express recombinant AR4 mutants. In this paper, we report a reliable method for expressing recombinant AR4 in Halobacterium salinarum L33 with a high yield of up to 20 mg/L. Experimental results show that the recombinant AR4 retains the light-driven proton pump characteristics and photo-cycling kinetics, similar to that in the native membrane. The functional role of bacterioruberin in AR4 and the trimeric packing of AR4 in its native and the recombinant forms are investigated through light-induced kinetic measurements, two-dimensional solid-state NMR experiments, dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). Such approaches provide new insights into structure-function relationships of AR4, and forms a basis for other archaeal rhodopsins.
    Biochimica et Biophysica Acta (BBA) - Bioenergetics 01/2015; 1847(4-5). DOI:10.1016/j.bbabio.2014.12.008 · 4.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Bacteriorhodopsin in purple membrane was reconstituted into different lipid vesicles. The effect of three different lipids on the structure and function of bacteriorhodopsin in lipid vesicles was studied by the observation on freeze-fracture eletron microscopy, the rotational diffusion of bacteriorhodopsin in lipid vesicles, the measurement of absorption spectrum, and the absorbance change with time. For these prepared samples, the results showed that DMPC was the stable lipid environment of bacteriorhodopsin; egg-pe causeed the loss of retinal chromophore of bacteriorhodopsin and it was not reversible change, cholesterol could stabilize the bacteriorhodopsin in lipid environment, but it caused the aggregation of bacteriorhodopsin.
    Chinese Science Bulletin 04/2002; 47(7). DOI:10.1360/02tb9129 · 1.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Atomic force microscope was employed to study the surface structure of purple membrane (PM) using contact mode in liquid. The surface structures of native PM and PM partly dissolved by detergent CHAPS were compared. Results show that 6 mmol/L CHAPS could induce some cracks and holes in PM. While Bateriorhodopsin (BR) was still presented as trimers in the two-dimensional hexagonal structure. We assume that it was caused by the interaction between CHAPS micellar and PM. Both absorption spectra and flash photolysis kinetic spectra indicated that BR’s biochemical functions have been changed.
    Chinese Science Bulletin 48(6):573-576. DOI:10.1360/03tb9122 · 1.37 Impact Factor