Genetic analysis of the active sites of lac repressor

Selection methods for the isolation of i(-d) and i(s) mutants are described. Two hundred and forty-seven i(-d) and 98 i(s) mutations have been localized by deletion mapping. All i(-d) mutations map in the region of the i gene, which codes for the aminoterminal part of the lac repressor, whereas i(s) mutations map in the middle of the i gene and at the proximal end of the i(-d) cluster.