FIG. 5.

Schematic representation of the strategy for generating a single point mutation in the B. anthracis rpoB gene. After cloning of a portion of the rpoB gene (∼2 kb in length), a single point mutation (A→G at position 1403) was introduced into the coding region of the rpoB gene along with a tag (T→C at position 1426, a silent mutation) by using the QuickChange mutagenesis kit (Stratagene). The wild-type rpoB DNA sequence on the chromosome was replaced by the mutated DNA sequence through reciprocal recombination. Gray boxes represent a portion of the rpoB gene. White boxes represent the original codons (CAG and TTA) in the wild-type rpoB gene. Black boxes represent the mutated codons (CGG and CTA) in the rpoB mutant.