Fig. 1.

Construction of an imp mutant strain. (A) Genomic organization of the imp locus in the wild-type and imp mutant. NMB0279 is annotated as a conserved hypothetical protein in the MC58 database (www.tigr.org). The survival protein A (surA) gene encodes a periplasmic chaperone involved in OMP biogenesis. rnb, ribonuclease II. Arrows delineate the DNA fragment used for transformation to obtain the mutant. (B) Immunoblot of cell envelopes of wild-type (lane 1) and imp mutant (lane 2) separated by SDS/PAGE and probed with anti-Imp antibodies. Molecular size markers are indicated in kDa.