1.B.60 The Omp50 Porin (Omp50 Porin) (Duf3373) Family

Thermophilic Campylobacters are enteropathogenic for humans. Bolla and coworkers showed that Omp50 is a Campylobacter species-specific porin produced in Campylobacter jejuni and Campylobacter lari but not in Campylobacter coli (Bolla et al. 2000; Bolla 2003). Dedieu et. al (2008) investigated regulation of the omp50 gene and found that its expression in C. jejuni was temperature-dependent but independent of growth phase and medium viscosity. The use of RT-PCR and omp50::lacZ fusions showed that growth temperature control occurred at the transcriptional level.

The promoter and coding sequence were cloned in an Escherichia coli-Campylobacter shuttle plasmid and transferred to E. coli and to a C. jejuni Omp50-deficient strain. Regulation of omp50 gene expression by growth temperature was observed in the recombinant C. jejuni strain, but not in E. coli. The same regulation was also observed in wild-type C. lari strains and in a C. coli strain supplemented by the plasmid, suggesting that omp50 expression is controlled by a mechanism conserved among Campylobacter species (Dedieu et al. 2008).

The Omp50 Porin family is most closely related to the Cyanobacterial Porin  (CBP) Family (1.B.23) and is a member of the Porin Superfamily I.