FIG. 1.

bldB gene and gene product. (a) bldB locus and relevant DNA fragments. The arrows below the chromosomal map indicate the DNA fragments used in bldB complementation (cloned into pRA1) and the two-hybrid analysis (cloned into pT18 and pT25). (b) BldB amino acid sequence, including the mutants tested for dimerization in the two-hybrid analysis. The red letters indicate highly conserved residues (Fig. 5). Deletion mutations (deletions of residues 1 to 10 [del1], 11 to 20 [del2], 1 to 47 [del3], 88 to 98 [del4], 78 to 98 [del5], and 71 to 98 [del6]) are represented by double-headed arrows, and frameshift mutations generated in random mutagenesis are indicated by FS1 and FS2.