FIG. 1.
Restriction maps of the dctA-orfQMP region of the E. coli chromosome. The inserts cloned in λ578, λ605, pGS753, pGS754, pGS928, pDctA, pOrfQMP, pDctA::Sp and pOrfQMP::Ap are shown along with E. coli DNA (thick black lines) and the Apr and Spr resistance cassettes (open bars). Relevant restriction sites are indicated: B, BamHI; Bc, BclI; Bg, BglII; Bs, BsphI; C, ClaI; E, EcoRI; H, HindIII; Hp, HpaI; P, PstI; S, SalI; and Sm, SmaI. Restriction sites within vector DNA are denoted by a v, and hybrid restriction sites no longer recognized by the corresponding enzymes are in parentheses. Solid arrows indicate the positions and polarities of relevant structural genes. The hatched bar represents the DNA fragment used as a hybridization probe, and a strongly predicted stem-loop structure is also indicated. Coordinates are from reference 51.