A spontaneous mutant of Escherichia coli with protein L24 lacking from the ribosome

Summary A spontaneous mutant that lacked ribosomal protein L24 was isolated and its derivatives investigated. The lesion responsible was close to, or in, rplX, the gene for protein L24. It led to a severe reduction in the amount of the large ribosomal subunit, even under permissive growth conditions. The mutation also led to a very slow growth rate and a temperature sensitive phenotype of carrier strains. Temperature indifferent secondary mutants frequently showed recovery of protein L24, but the protein was usually in a form larger than wildtype. Other secondary mutants had acquired an external suppressor that resulted in the simultaneous alteration of several other ribosomal proteins as well as the fractional presence of protein L24. Secondary mutants had normal amounts of the large ribosomal subunit, but it sedimented more slowly than normal.