[2D-1H-NMR-study of the conformation of transmembrane segments of C, E, and G bacteriorhodopsin]

Abstract

Conformations of synthetic peptides, analogues of the membrane spanning segments C (residues 67-106), E (128-162) and G (190-233) of bacteriorhodopsin Halobacterium halobium were studied by two-dimensional 1H-NMR spectroscopy. Peptides were solubilized in the mixture chloroform-methanol (1:1), 0.1 M LiC1O4. The spectrum resonances were assigned by means of phase-sensitive DQF-COSY, TOCSY and NOESY techniques. Interproton nuclear Overhauser effects were derived from NOESY spectra. Amide protons with slow deuterium exchange rates were determined. Analysis of the obtained data showed that segments C, E and G form right-handed alpha-helices including residues 77-101, 131-159 and 198-227, respectively.