Dynamic properties of bacteriorhodopsin in purple membranes upon heat treatment.
Reversible temperature-dependent conformational changes in bacteriorhodopsin of the purple membranes from Halobacterium halobium have been studied by the method of deuterium exchange. A noticeable increase in the mobility of structured peptide groups in bacteriorhodopsin was revealed upon reorganization of the supermolecular structure at about 60 degrees C. In the supermolecular structure formed, bacteriorhodopsin molecules have no contacts with external medium at 75-80 degrees C. Membrane destruction results in a drastic increase in molecular mobility within the narrow temperature range 100-110 degrees C. The effects observed are induced by predenaturation changes in the bacteriorhodopsin structure and rearrangements in the structure of a protein-lipid complex. The temperature dependence of the number of peptide groups involved in reversible conformational rearrangements is in good agreement with the microcalorimetry data.
Shnyrov
V L
VL
Institute of Biological Physics, U.S.S.R. Academy of Sciences, Pushchino, 142292 Moscow Region, U.S.S.R.
Sukhomudrenko
A G
AG