FIG. 3.

Genetic map of the gudB region (41) and plasmids carrying different parts of this region. The restriction sites are abbreviated as follows: Bg, BglII; Bt, BstYI; E, EcoRI; H, HindIII; K, KpnI; S, StyI; and V, EcoRV. Only relevant EcoRV, HindIII, and StyI sites are shown. The KpnI site of the insert in pBB902 and derivative plasmids was constructed by PCR. Plasmid pBB933 is a derivative of pJPM82 (7); other plasmids are derivatives of pBB544 (7). Construction of some plasmids is described in Materials and Methods; other plasmids were constructed by deleting or subcloning fragments of the gudB region. The location of the gudB transcription initiation site (see Results) is indicated by the arrow. The 1.9-kb tet cassette is not drawn to scale. x denotes the location of the gudB1 mutation within pBB928.