FIG. 1.

Deletions of mrcA and neighboring genes in E. coli. (A)Gene order downstream of mrcA in the parental strain, E. coli CS109. (B) Extent of deletion created in E. coli CS13-2K, previously reported to encompass only mrcA (2). The segment from the XhoI site in mrcA to the BspDI site in yrfF was replaced by the res-npt-res cassette (4). (C) Extent of the new mrcA deletion in E. coli BMCS04-1K reported in this work. The entire mrcA gene from the initiation codon to the termination codon was replaced by the res-npt-res cassette (4). Abbreviations: B, BamHI; E, EcoRI; DI, BspDI; H, HindIII; X, XhoI.