Purification and Properties of a Ribose-binding Protein from Escherichia coli

Abstract

Abstract Escherichia coli W3092 has a specific permease for ribose with a Km of 0.3 µm. An osmotic shock releasable ribosebinding protein was purified to homogeneity. The ribosebinding protein has an apparent molecular weight of 29,500 as judged by gel titration and sodium dodecyl sulfate polyacrylamide gel electrophoresis and an isoelectric point of 6.6. The binding protein is specific for d-ribose and 1 molecule of ribose is bound per molecule of protein with a dissociation constant of 0.13 µm. The high specificity for binding and transport also correspond with the ribose chemotactic system in E. coli (Adler, J., Hazelbauer, G. L., and Dahl, M. M. (1974) J. Bacteriol. 115, 824). The ribose-binding protein of E. coli cross-reacts immunologically with serum prepared against the Salmonella typhimurium ribose-binding protein but does not cross-react with sera prepared against a number of other binding proteins including the E. coli galactose-glucose-binding protein.