Indirect role of adenylate cyclase and cyclic AMP in chemotaxis to phosphotransferase system carbohydrates in Escherichia coli K-12.

Most strains of Escherichia coli K-12 lacking the enzyme adenylate cyclase showed normal chemotaxis toward carbohydrates taken up and phosphorylated by the phosphoenolpyruvate-dependent carbohydrate: phosphotransferase system. The normal reaction was observed even in the absence of externally added cyclic adenosine 3',5'-phosphate, provided that the enzyme II chemoreceptors and the flagella were synthesized. In the CA8306 series of strains, however, the cya-854 deletion abolished chemotaxis toward phosphotransferase system carbohydrates even though growth on and transport of these carbohydrates were not affected. This abnormal phenotype was due to the presence of a specific mutation in strain CA8306 which mapped in or close to the crp locus and apparently prevented expression of a hitherto unidentified molecule involved in enzyme II-mediated signal transduction. This molecule is neither a pts protein nor a cyclic adenosine 3',5'-phosphate-binding protein.