Open AccessMolecular Organization in Bacterial Cell Membranes
Author(s) -
AZOCAR Omar,
MUÑOZ Emilio
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10784.x
Subject(s) - dithiothreitol , iodoacetic acid , iodoacetamide , membrane , streptomyces albus , biochemistry , chemistry , escherichia coli , gel electrophoresis , polyacrylamide gel electrophoresis , chromatography , bacteria , biology , cysteine , streptomyces , enzyme , gene , genetics
Plasma membranes from Streptomyces albus had 5.2 mol of sulfhydryl groups and 6 mol of disulfide bridges/50 kg protein whereas Escherichia coli membranes had 3.4 mol sulfhydryl groups and 4 mol disulfide bridges/50 kg protein. About 66% of the sulfhydryl groups of S. albus membranes and 22% of those of E. coli membranes were readily accessible to titration with 5,5′‐dithiobis(2‐dinitrobenzoic acid). o‐[(3 Hydroxymercuri‐2‐methoxypropyl)‐carbamyl]‐phenoxyacetic acid (mersalyc acid). and p‐chloromercuribenzoate were effective in solubilizing membrane proteins from the two bacteria. Other sulfhydryl group reagents, such as N‐ethylmaleimide, iodoacetamide and iodoacetic acid, were less effective. Dithiothreitol affected the dodecylsulphate gel electrophoresis patterns of S. albus membranes and soluble fractions. This effect resulted from the reduction of pre‐existing disulfide intramolecular bridges and some interchain disulfide formed during solubilization and/or storage. Dithiothreitol also affected the dodecylsulphate gel electrophoresis patterns of E. coli membranes and their soluble fractions. These results suggest that sulfhydryl groups and disulfide bridges play a role in the structural organization of these prokaryotic membranes.