FIG. 1.

The mra locus and the plasmids used in this work. The scale at the top is in kilobase pairs. Coding regions are shown as boxes, labelled as follows: z, mraZ; w, mraW; L, ftsL; I, ftsI (pbpB); E, murE; F, murF; Y, mraY; D, murD; W, ftsW; G, murG; C, murC; B, ddlB; Q, ftsQ; A, ftsA; Z, ftsZ; V, envA. The approximate positions of known promoters are shown as the points of the arrowheads, and the terminator is shown as a stem loop. The positions of frameshift insertions in plasmids are shown as asterisks.