Protein phosphorylation in Escherichia coli L. form NC-7

Wall-less L-forms of Escherichia coli constitute an interesting, and relati vely underused, model system for numerous studies of bacterial physiology i ncluding the cell cycle, intracellular structure and protein phosphorylatio n. Total extracts of the L-form revealed a pattern of protein phosphorylati on similar to that of an enteropathogenic strain but very different from it s parental K-12 strain. In particular, the L-form extract revealed phosphor ylation On tyrosine of a protein Important In pathogenesis, TypA, and calci um-specific phosphorylation of a 40 kDa protein. Two new phosphoproteins we re identified in the L-form as the DNA-binding protein Dps, and YfiD, a pro tein of 14 kDa with homology to pyruvate formate-lyase and a region contain ing a tRNA cluster in bacteriophage T5.