THE EFFECTS OF DELETIONS, POINT MUTATIONS, REVERSIONS AND SUPPRESSOR MUTATIONS ON THE TWO COMPONENTS OF THE TRYPTOPHAN SYNTHETASE OF ESCHERICHIA COLI

Abstract

The effects of deletions, point mutations, suppressor mutations and reversions on the 2 components of the TSase of E. coli were examined. It was found that mutants lacking the A and B genes also lack the A and B proteins. Point mutants at the A locus and point mutants at the B locus formed either an altered form of the corresponding protein (cross reacting material = CRM) or none at all. In each instance where an altered protein was produced it was enzymatically active in one of the 3 reactions in which the normal component participates. Full revert ants obtained from A and B mutants formed what appears to be normal components while partial revertants and some suppressed mutants produced either a mixture of normal and abnormal proteins or a new species of active protein. Suppressed mutants derived from non-CRM formers produced relatively little of one of the 2 components suggesting that some defect in A or B protein formation exists in these strains.