Open Access1 H‐ 15 N‐NMR studies of bacteriorhodopsin Halobacterium halobium
Author(s) -
OREKHOV Vladislav Yu.,
ABDULAEVA Galina V.,
MUSINA Larisa Yu.,
ARSENIEV Alexander S.
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb17412.x
Subject(s) - bacteriorhodopsin , halobacterium , halobacteriaceae , chemistry , antiparallel (mathematics) , crystallography , nuclear magnetic resonance spectroscopy , heteronuclear molecule , stereochemistry , proton nmr , membrane , biochemistry , physics , halobacterium salinarum , quantum mechanics , magnetic field
Series of uniformly and selectively 15 N‐labeled bacteriorhodopsins of Halobacterium halobium (strain ET 1001) were obtained and a 1 H‐ 15 N‐NMR study was performed in methanol/chloroform (1:1) and 0.1 M NH 4 CHOO, medium which mimics that in the membrane in vivo . Less than half of the cross‐peaks expected from the amino acid sequence of uniformly 15 N‐labeled bacteriorhodopsin were observed, using heteronuclear 1 H‐ 15 N coherence spectroscopy. In order to assign the observed cross‐peaks, a selective 15 N‐labeling of amino acid residues (Tyr, Phe, Trp, Lys, Gly, Leu, Val or Ile) was carried out and 1 H‐ 15 N‐NMR spectra of bacteriorhodopsin and its fragments C1 (residues (72–231), C2 (residues 1–71), B1 (residues 1–155) and BP2 (residues 163–231) were investigated. By this procedure, all observed 1 H‐ 15 N cross‐peaks of the entire bacteriorhodopsin were found to belong to the transmembrane segments A, B and G. The cross‐peaks from four (C, D, E and F) helical bundles (79–189 residues) were missed. These results clearly indicate that dynamic processes occur in the four helice bundle. The significance of this, in respect to bacteriorhodopsin functioning, is discussed.