Disease relevance of ECs3104

• OmpC and PhoE porins of Escherichia coli were examined by the patch-clamp technique following reconstitution in liposomes, and were observed primarily in the open (conducting) state [1].
• The hybrid gene products were normally expressed and they were characterized with respect to functions and properties in which the native OmpC and PhoE proteins differ, such as pore characteristics, the receptor activity for phages and the binding of specific antibodies [2].
• Because RseP is shown to be no longer essential in a strain lacking OmpA and OmpC, we conclude that RseP, which is required for normal sigma(E) activation, prevents toxicity due to the presence of two specific outer membrane proteins that are down-regulated by RseX [3].
• The Salmonella typhi ompS1 gene codes for an outer membrane protein of the OmpC/OmpF porin family [4].
• Ileal lesions of 36.4% of patients with Crohn's disease (CD), an inflammatory bowel disease in humans, are colonized by pathogenic adherent-invasive Escherichia coli (AIEC), and high levels of antibodies directed against E. coli OmpC are present in 37-55% of CD patients [5].

High impact information on ECs3104

• In addition, several PhoE mutants with amino acid substitutions and insertions in either the L3 or L4 loop of the monomer exhibited pressure sensitivity comparable with the wild-type OmpC porin [1].
• Analysis of amino acid sequences reported for the major outer membrane proteins of Escherichia coli, including the porins (OmpF, OmpC, and PhoE), the phage lambda receptor (LamB), and another protein (OmpA), revealed several regions of local homology that is statistically significant [6].
• RseX activity was shown to confer an Hfq-dependent coordinate OmpA and OmpC down-regulation [3].
• Three linker mutants give rise to an OmpF(+) OmpC(-) phenotype, but the defects are not due to a shared molecular mechanism [7].
• EnvZ, a histidine kinase/phosphatase in Escherichia coli, responds to the osmolarity changes in the medium by regulating the phosphorylation state of the transcription factor OmpR, which controls the expression levels of outer membrane porin proteins OmpF and OmpC [8].

Chemical compound and disease context of ECs3104

• The histidine kinase/phosphatase EnvZ helps Escherichia coli adapt to osmotic shock by controlling the phosphorylation state of the transcription factor OmpR, which regulates the levels of the outer membrane porin proteins OmpF and OmpC [9].
• The phage resistance seen in these mutants could be a result of both the presence of defective LPS and reduced OmpC levels [10].
• OmpC, a major outer-membrane protein, is highly expressed when Salmonella typhi is grown in nutrient broth (NB) of either low (NB + 0% sucrose) or high (NB + 20% sucrose) osmolarity [11].
• The antigenic determinants of Salmonella typhimurium OmpC were investigated by the analysis of cyanogen bromide (CNBr)-generated porin peptides with antiporin monoclonal antibodies (MAbs) [12].
• Studies on Salmonella typhi and Salmonella typhimurium outer membrane proteins have shown that the relative position of OmpC porin in sodium dodecyl sulfate.polyacrylamide gel electrophoresis undergoes an important shift when the concentration of ammonium persulfate in the running gel is increased from 6 to 12 mM [13].

Biological context of ECs3104

• Localization and membrane topology of EnvZ, a protein involved in osmoregulation of OmpF and OmpC in Escherichia coli [14].
• Mutants lacking MDO showed imparied chemotaxis on tryptone swarm plates, a reduced number of flagella, and an enhanced expression of the OmpC porin [15].
• The effects of four polyamines (putrescine, cadaverine, spermidine, and spermine) on the activity of bacterial porins OmpC and OmpF were investigated by electrophysiology [16].
• Expression of these proteins from a multicopy plasmid vector in E. coli resulted in a decrease in the level of the outer membrane porin protein OmpF and an increase in the level of the outer membrane porin protein OmpC [17].
• The differential expression of the outer membrane porin proteins OmpC and OmpF and analysis of lacZ fusions with promoter regions sensitive to supercoiling suggests that low-level Hc1 expression results in a net relaxation of chromosomal DNA [18].

Anatomical context of ECs3104

• We therefore investigated the expression of OmpC and its role in the interaction of CD-associated adherent-invasive E. coli strain LF82 with intestinal epithelial cells [5].
• Single OmpC porin channels have been reconstituted in planar bilayer membranes [19].
• Evidence from this study supports a role for the OmpC protein in initial recognition by macrophages and distinguishes regions of this protein that potentially participate in host-cell recognition of bacteria by phagocytic cells [20].
• The effects of a hydrophobic peptide segment inserted into the amino-terminal region of the mature domain of OmpC, an outer membrane protein, on its translocation across the cytoplasmic membrane was studied [21].
• In contrast, the supernatants from the immunization with outer membrane preparation lacking S. typhi Ty2 OmpC induced a significantly reduced bactericidal capacity of U937 cells [22].

Associations of ECs3104 with chemical compounds

• OmpF and OmpC, although highly homologous, have distinct sensitivities to modulation, especially by spermine [16].
• By measuring the permeability of porin channels in intact cells suspended in solutions of widely different ionic strengths, it was shown that changing Donnan potential from 5 mV to approximately 100 mV had no effect on the permeability of either OmpF or OmpC porin channel toward a zwitterionic compound, cephaloridine [23].
• The gene appears to encode a secretory precursor of OmpC protein consisting of a total of 367 amino acid residues with a signal peptide of 21 amino acid residues at its NH2-terminal end [24].
• At low substrate concentration (0.7 microM), permeation of glycine betaine was entirely dependent on the OmpF and OmpC porins [25].
• The possibility that heterologous nitrate reductases could be formed in vivo is discussed with reference to the existence of porin heterotrimers of the outer membrane proteins OmpC, OmpF and PhoE [26].

Analytical, diagnostic and therapeutic context of ECs3104

• Western blot analyses of cell extracts with anti-TolA antibodies indicated that TolA forms high molecular weight complexes specifically with trimeric OmpF, OmpC, PhoE and LamB, but not with OmpA [27].
• The three-dimensional structure of OmpC has been determined to 2.0 A resolution by X-ray crystallography [28].
• Electron microscopy of unstained, frozen-hydrated OmpC reveals the trimeric pore structure with equal clarity [29].
• Immunoprecipitation of labeled proteins showed no evidence of accumulation of uncleaved precursor forms of OmpA or maltose-binding protein following induction of OmpC overexpression [30].
• Two oligonucleotides encoding the N-terminal portion of the 38-kDa OMP and C-terminal portion of OmpC were used to amplify the 38-kDa gene by PCR [31].

References