Bordetella pertussis 18323 produces a bvg-regulated 39.1-kDa porin-like protein, OmpQ. OmpQ had 61% similarity to the major porin of B. pertussis and contains conserved regions common to both the neisserial and enteric porin families. The results of Southern blot analysis indicate that strains of Bordetella parapertussis and Bordetella bronchiseptica but not Bordetella avium contain this gene.

The ion permeation process, driven by a membrane potential through an outer membrane protein, OmpF porin of Escherichia coli, was simulated by molecular dynamics. A Na+ ion, initially placed in the solvent region at the outer side of the porin channel, moved along the electric field passing through the porin channel in a 1.3 nsec simulation; the permeation rate was consistent with the experimen...

The crystal structure of a non-specific porin from Paracoccus denitrificans at 3.1 A resolution has been solved by molecular replacement using the porin from Rhodopseudomonas blastica as the search model. Paracoccus porin is very similar to other non-specific porins of known structure: a trimer of 16 stranded beta-barrels each with a central pore constricted by a long extracellular loop folding...

Protein K is an outer membrane protein found in pathogenic encapsulated strains of Escherichia coli. We present evidence here that protein K is structurally and functionally related to the E. coli K-12 porin proteins (OmpF, OmpC, and PhoE). Protein K was found to cross-react with antibody to OmpF protein and to share 8 out of 17 peptides in common with the OmpF protein. Strains that are OmpC po...

The PhoE porin of Escherichia coli is induced by phosphate deprivation and when purified, forms moderately anion-selective channels in lipid bilayer membranes. To further investigate the basis of anion selectivity, PhoE was chemically acetylated with acetic anhydride. Acetylation modified the mobility and staining characteristics of the PhoE porin on SDS-polyacrylamide gel electrophoresis but t...

Mitochondrial porin, or voltage-dependent anion channel, is a pore-forming protein first discovered in the outer mitochondrial membrane. Later investigations have provided indications for its presence also in other cellular membranes, including the plasma membrane, and in caveolae. This extra-mitochondrial localization is debated and no clear-cut conclusion has been reached up to now. In this w...

The major outer membrane porin (PorB) expressed by Neisseria gonorrhoeae plays multiple roles during infection, in addition to its function as an outer membrane pore. We have generated a panel of mutants of N. gonorrhoeae strain FA1090 expressing a variety of mutant porB genes that all function as porins. We identified multiple regions of porin that are involved in its binding to the complement...

The outer membrane permeability of Serratia marcescens was studied by comparing porin-deficient mutants with their parental strains. Omp1-deficient strains were selected by moxalactam resistance, whereas mutants lacking the Omp2 porin were obtained by experimental infection with the SMP2 phage, whose primary receptor is the Omp2 porin. The role of porins was demonstrated in quinolone accumulati...

Escherichia coli porin OmpF and Pseudomonas aeruginosa porin protein P were eluted from sodium dodecyl sulfate-polyacrylamide gels. The resultant porin preparations were found to be devoid of detectable lipopolysaccharide (LPS) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining for LPS, direct enzyme-linked immunosorbent assays with LPS-specific monoclonal antibodi...

The isolate major outer membrane protein from Rhodopseudomonas capsulata St. Louis (ATCC 23782) has a high porin activity in reconstituted phospholipid liposomes. The pore size of the homooligomeric porin with subunits of Mr 33,000 was determined to be about 0.8 nm in radius. Circular dichroism data revealed major portions of the beta structure. Heating of the oligomer resulted in monomer forma...