Biogenesis of β-barrel membrane proteins is a complex, multistep, and as yet incompletely characterized process. The bacterial porin family is perhaps the best-studied protein family among β-barrel membrane proteins that allows diffusion of small solutes across the bacterial outer membrane. In this study, we have identified residues that contribute significantly to the protein-protein interacti...

The Escherichia coli OmpF (outer-membrane protein F; matrix porin) is a homotrimeric beta-barrel and a member of the bacterial porin superfamily. It is the best characterized porin protein, but has resisted attempts to refold it efficiently in vitro. In the present paper, we report the discovery of detergent-based folding conditions, including dodecylglucoside, which can create pure samples of ...

We have described a gene coding for an Enterobacter cloacae protein, provisionally called OmpX (J. Stoorvogel, M. J. A. W. M. van Bussel, J. Tommassen, and J. A. M. van de Klundert, J. Bacteriol. 173:156-160, 1991). In the work reported here, OmpX was localized in the cell envelope by means of sucrose gradient fractionation of membrane vesicles. Overproduction of OmpX in Escherichia coli from a...

The function and novel regulation of OpnP of the symbiotic/pathogenic bacterium, Xenorhabdus nematophilus was studied. In vitro pore-function analysis of purified OpnP indicated that the single-channel-conductance values were similar to that measured for the porin protein, OmpF, of Esherichia coli. Nucleotide sequence analysis revealed that the mature OpnP protein contained 348 amino acid resid...

209-Pos Board B88 The Biophysics Of Antibiotics Translocation Through OmpF Revealed By Computer Simulations Eric Hajjar1, Amit Kumar1, Enrico Spiga1, Jean-Marie Pages2, Kozhinjampara Mahendran3, Tivadar Mach3, Andrey Bessonov3, Mathias Winterhalter3, Paolo Ruggerone1, Matteo Ceccarelli1. University of Cagliari, Cagliari, Italy, 2Université de la Méditerranée, Marseille, France, Jacobs Universit...

We used patch clamp analysis to compare the electrophysiological behavior of two related porins from Escherichia coli, the anion-specific PhoE and the cation-selective OmpF. Outer membrane fractions were obtained from strains expressing just one of these porin types, and the channels were reconstituted into liposomes without prior purification. We show that the orientation of the reconstituted ...

The assembly of outer membrane proteins of Escherichia coli was examined using the OmpF porin as a model. Since this protein is made as a precursor, which is processed to a protein of Mr 37,000 before being assembled into trimers in the outer membrane, we synthesized a modified OmpF, which lacked 16 out of 22 amino acid residues from its signal sequence, in a coupled transcription-translation s...

Yersinia enterocolitica is an important zoonotic pathogen, which seriously endangers food-safety risk. In this study, the recombinant outer membrane protein OmpF and its antibody were prepared coupled with immunomagnetic beads (IMBs) to capture Y. in food samples, combining quantitative PCR detection primers of virulence factor gene foxA for contamination. The results showed that efficiency app...

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...