Identification of polypeptides necessary for chemotaxis in Escherichia coli

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Abstract
Molecular cloning techniques were used to construct E. coli-[phage].lambda. hybrids that contained many of the genes necessary for flagellar rotation and chemotaxis. The properties of specific hybrids that carried the classical cheA and cheB loci were examined by genetic complementation and by measuring the capacity of the hybrids to direct the synthesis of specific polypeptides. The results of these tests with .lambda. hybrids and with a series of deletion mutations derived from the hybrids redefined the cheA and cheB regions. Six genes were resolved: cheA, cheW, cheX, cheB, cheY and cheZ. They directed the synthesis of specific polypeptides with the following apparent MW: cheA, 76,000 and 66,000; cheW, 12,000; cheX, 28,000; cheB, 38,000; cheY, 8000; and cheZ, 24,000. The presence of another gene, cheM, was inferred from the protein synthesis experiments. The cheM gene directed the synthesis of polypeptides with apparent MW of 63,000, 61,000 and 60,000. The synthesis of all of these polypeptides is regulated by the same mechanisms that regulate the synthesis of flagellar-related structural components.