Studies on Escherichia coli mutants which block bacteriophage morphogenesis.

We have previously reported the isolation of E. coli groE mutants, which block lambda head morphogenesis. Further analysis of these mutants showed that many are temperature-sensitive for bacterial growth or block the growth of the unrelated phages T4 and T5. We have established the existence of a second groE gene, which we call groES, that is different from the previously described groE gene encoding a 65,000-Mr polypeptide (Georgopoulos and Hohn, 1978; Hendrix and Tsui, 1978) and which is renamed groEL. Genetic and biochemical studies of lambda groE+ transducing phages and their mutant derivatives show that these two genes are closely linked and that the groES gene codes for a polypeptide of 15,000-Mr. Bacterial groEL- or groES- mutants exhibit the same growth kinetics and phenotype at high temperature and lambda proheads have the same protein composition in both classes of mutants.