FIG. 3.
Strategy for obtaining an SHI operon deletion and PCR analyses of the cytoplasmic hydrogenase operon deletions. (A) The SHI operon genome region is shown with the SHI operon deletion plasmid with 1-kb regions from up- and downstream of the operon for homologous recombination and also containing the Pgdh-pyrF cassette for selection of uracil prototrophy. Homologous recombination can occur at either the upstream or downstream SHI operon flanking regions, integrating the plasmid into the genome and generating a strain that is a uracil prototroph. PF0891, PF0892, PF0893, and PF0894 represent the genes coding for the SHI beta, gamma, delta, and alpha subunits, respectively. (B) Gel depicting PCR products of the SHI and SHII operon genome regions in the ΔSHI, ΔSHII, and ΔSHI ΔSHII strains compared to the COM1 strain, amplified by primers with at least one primer outside the homologous recombination regions.