SOLUBILIZATION OF PROTEIN ACCOMPANYING LOSS OF PERMEABILITY OF ESCHERICHIA COLI

Abstract

Rogers, Dexter (Utah State University, Logan). Solubilization of protein accompanying loss of permeability of Escherichia coli . J. Bacteriol. 88: 279–292. 1964.—Two methods were studied for altering glucose permeability of Escherichia coli , and changes in protein and phosphorus composition were compared with changes in permeability. Protein was solubilized by incubating the cells at pH 7.3 in the presence of chloramphenicol, under conditions known to destabilize permeability. No protein was solubilized at pH 5.3, where permeability is stable. The solubilized protein was one of the first proteins to be extracted from the cells under mild conditions. Permeability was also altered by varying the culture age. It was maximal for logarithmic growth phase cultures, and it decreased rapidly in cultures in the stationary growth phase. Permeability correlated with the ratio of insoluble protein to soluble protein of the cells. Chromatographic analysis of an extract of cells treated at pH 7.3 revealed the presence of one additional protein fraction that was not present in an extract of cells treated at pH 5.3. The solubilized protein was precipitable with uranyl ion, which is a non-penetrating inhibitor of glucose transport in intact cells. Changes in phosphorus composition preceded changes in permeability and protein composition. These changes suggested that a phosphorus metabolite might contribute to the activity of the permeation process.