Studying the spatial organization of membrane proteins by means of tritium stratigraphy: bacteriorhodopsin in purple membrane.
The topography of bacteriorhodopsin (bR) in situ was earlier studied by using the tritium bombardment approach [Eur. J. Biochem. 178 (1988) 123]. Now, having the X-ray crystallography data of bR at atom resolution [Proc. Natl. Acad. Sci. 95 (1998) 11673], we estimated the influence of membrane environment (lipid and protein) on tritium incorporation into amino acid residues forming transmembrane helices. We have determined the tritium flux attenuation coefficients for residues 10-29 of helix A. They turned out to be low (0.04+/-0.02 A(-1)) for residues adjacent to the lipid matrix, and almost fourfold higher (0.15+/-0.05 A(-1)) for those oriented to the neighboring transmembrane helices. We believe that tritium incorporation data could help modeling transmembrane segment arrangement in the membrane.
Shishkov
A V
AV
N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Russia.
Ksenofontov
A L
AL
Bogacheva
E N
EN
Kordyukova
L V
LV
Badun
G A
GA
Alekseevsky
A V
AV
Tsetlin
V I
VI
Baratova
L A
LA
D001436:Bacteriorhodopsins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008565:Membrane Proteins / Q000737:chemistry*; D014316:Tritium
D008565:Membrane Proteins; D014316:Tritium; D001436:Bacteriorhodopsins