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

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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.