FIG. 1.

Sequence alterations corresponding to Rif^r mutations. Changes in the nucleotide sequence and the corresponding amino acid residue for the representative Rif^r allele are indicated by the arrows, respectively, above and below the sequence of the wild-type UA802 rpoB gene (numbers in parentheses are alleles corresponding to those listed in Table 3). The sequence covers the region of amino acid residues 524 to 587. The lowercase letters above the sequence indicate the nucleotides in the 26695 rpoB gene that diverge from the rpoB gene of UA802. Note that the majority of divergence between these two wild-type strains is due to the base substitutions in the third positions of the codons (silent mutations). In contrast, the mutations that confer Rif^r are all in the first or second positions of codons and lead to an amino acid change.