Identification of a second Escherichia coli groE gene whose product is necessary for bacteriophage morphogenesis.

Previous work has uncovered the existence of an Escherichia coli locus, groE, that is essential for bacterial growth, lambda phage and T4 phage head morphogenesis, and T5 phage tail assembly. Our genetic and biochemical analyses of lambda groE+ transducing phages and their deletion and point mutant derivatives show that the groE locus consists of two closely linked genes. One groE gene, groEL, has been shown to encode the synthesis of a 65,000 Mr polypeptide, whereas the second, groES, codes for the synthesis of a 15,000 Mr polypeptide. About half of the groE- bacterial isolates fall into the groES complementation group. GroE mutations in either gene cause similar phenotypes, with respect to lambda phage head morphogenesis and bacterial growth at nonpermissive temperatures.