An amber mutation in the gene rpsA for ribosomal protein S1 in Escherichia coli.

An amber mutation has been induced in the gene rpsA (which codes for ribosomal protein S1) of Escherichia coli K-12 strain in the presence of an amber suppressor (supD) and mutations sueA, sueB and sueC that additively enhance the efficiency of suppression. That the amber mutation has occurred in the gene rpsA was confirmed by complementation with a plasmid which carried the wild-type allele of rpsA. The mutation is lethal in the absence of an amber suppressor, indicating that ribosomal protein S1 is indispensable to E. coli.