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.
This family belongs to the Outer Membrane Pore-forming Protein I (OMPP-I) Superfamily .
References:
Bolla, J.M. (2003). Purification of Omp50, a minor porin of Campylobacter jejuni. Methods Mol Biol 228: 131-138.
Bolla, J.M., E. Dé, A. Dorez, and J.M. Pagès. (2000). Purification, characterization and sequence analysis of Omp50,a new porin isolated from Campylobacter jejuni. Biochem. J. 352Pt3: 637-643.
Dedieu, L., J.M. Pagès, and J.M. Bolla. (2008). The omp50 gene is transcriptionally controlled by a temperature-dependent mechanism conserved among thermophilic Campylobacter species. Res. Microbiol. 159: 270-278.
Hazlett, K.R., D.L. Cox, M. Decaffmeyer, M.P. Bennett, D.C. Desrosiers, C.J. La Vake, M.E. La Vake, K.W. Bourell, E.J. Robinson, R. Brasseur, and J.D. Radolf. (2005). TP0453, a concealed outer membrane protein of Treponema pallidum, enhances membrane permeability. J. Bacteriol. 187: 6499-6508.
Luthra, A., G. Zhu, D.C. Desrosiers, C.H. Eggers, V. Mulay, A. Anand, F.A. McArthur, F.B. Romano, M.J. Caimano, A.P. Heuck, M.G. Malkowski, and J.D. Radolf. (2011). The transition from closed to open conformation of Treponema pallidum outer membrane-associated lipoprotein TP0453 involves membrane sensing and integration by two amphipathic helices. J. Biol. Chem. 286: 41656-41668.
Examples:
TC#	Name	Organismal Type	Example
1.B.60.1.1	*The outer membrane, monomeric, large conductance, cation-selective Omp50 porin of 453 aas (Bolla et al.* 2000).**	ε-Proteobacteria	*Omp50 of Campylobacter jejuni* (Q0P986)**

1.B.60.1.10	Uncharacterized protein of 443 aas and 1 N-terminal TMS.		UP of Bdellovibrio bacteriovorus

1.B.60.1.2	Putative outer membrane porin, Despr_2770	δ-Proteobacteria	*Omp of Desulfobulbus propionicus* (E8RCF8)**

1.B.60.1.3	Putative outer membrane porin, Shew185-0459	γ-Proteobacteria	*Omp of Shewanella baltica* (A6WII8)**

1.B.60.1.4	Putative outer membrane porin, Glov_2218	δ-Proteobacteria	*Omp of Geobacter lovleyi* (B3E4B3)**

1.B.60.1.5	Putative outer membrane porin Rfer_3633	β-Proteobacteria	*Omp of Rhodoferax ferrireducens* (Q21SB8)**

1.B.60.1.6	Putative outer membrane porin, Flexsi_1177	Deferribacteres	*Omp of Flexistipes sinusarabici* (F8E6J5)**

1.B.60.1.7	Putative outer membrane porin	δ-Proteobacteria	*Omp of Anaeromyxobacter dehalogenans* (Q2IPL5)**

1.B.60.1.8	Putative outer membrane porin	ε-Proteobacteria	*Omp of Caminibacter mediatlanticus* (A6DB68)**

1.B.60.1.9	Putative outer membrane porin	δ-Proteobacteria	*Omp of Haliangium ochraceum* (D0LXF9)**