Disease relevance of ompG

• Although ompG DNA was present in all E. coli strains examined so far, its expression under laboratory conditions was seen only due to rare chromosomal mutations [1].
• LamB is a trimeric outer membrane porin for maltodextrins as well as the bacteriophage lambda receptor in Escherichia coli [2].
• Among patients with Crohn's disease, serum responses have been documented to microbial and autoantigens (antibodies to the Escherichia coli outer-membrane porin C and the Pseudomonas fluorescens-associated sequence I2, antisaccharomyces cerevisiae antibody (ASCA), and perinuclear antineutrophil cytoplasmic antibodies) [3].
• CONCLUSIONS: I2 and anti-Escherichia coli outer membrane porin C are associated with Crohn's disease phenotypes, and patients with the highest level of serum reactivity toward an increasing number of microbiota have the greatest frequency of strictures, internal perforations, and small bowel surgery [4].
• The outer membrane porin molecule of Neisseria gonorrhoeae is known as protein I (PI) [5].

High impact information on ompG

• The EnvZ molecule has a membrane topology similar to Tar and is a putative osmosensor that is required for osmoregulation of the genes for the major outer membrane porin proteins, OmpF and OmpC [6].
• BACKGROUND & AIMS: Crohn's disease patients can be characterized by antibody responses against Crohn's disease-related bacterial sequence, Escherichia coli outer membrane porin C, Saccharomyces cerevisiae (oligomannan), and neutrophil nuclear antigens [4].
• Immunoglobulin A enzyme-linked immunosorbent assays to ASCA, outer-membrane porin C, or I2 and immunoglobulin G enzyme-linked immunosorbent assay to ASCA and ANCA determined the presence and level of antibodies [3].
• We identified one of the major Z-DNA binding proteins of this fraction, not as a protein involved in gene regulation or genetic recombination, but rather as an outer membrane porin protein [7].
• In Escherichia coli the ompF gene encodes a major outer membrane porin protein that is differentially regulated by the OmpR protein [8].

Chemical compound and disease context of ompG

• One single lysine residue is responsible for the special interaction between polyphosphate and the outer membrane porin PhoE of Escherichia coli [9].
• EnvZ is a sensory histidine kinase in Escherichia coli to regulate the phosphorylation of OmpR, its cognate response regulator, required for the expression of genes for outer membrane porin proteins [10].
• The sucrose-specific outer membrane porin ScrY of Salmonella typhimurium was isolated from Escherichia coli K-12 strain KS 26 containing the plasmid pPSO112 [11].
• Negative regulation of the Pseudomonas aeruginosa outer membrane porin OprD selective for imipenem and basic amino acids [12].
• Vibrio anguillarum serotype O2 strains express a 40-kDa outer membrane porin protein [13].

Biological context of ompG

• Molecular characterization of cog-192 revealed that it is a large chromosomal deletion extending from the 3' end of pspA through to the 5' end of an open reading frame located immediately upstream of ompG [1].
• Cluster analysis of these antibody responses yielded 4 groups: ASCA, outer-membrane porin C/I2, perinuclear antineutrophil cytoplasmic antibodies, or no/low response [3].
• Fragments of the gene encoding the major outer membrane porin protein (MOMP) of Chlamydia trachomatis serovar L1 were ligated into the pUC plasmid vectors to give a series of overlapping recombinants expressing MOMP from the lac promoter [14].
• The gene bglH present in the bgl operon of Escherichia coli, responsible for uptake and fermentation of beta-glucosides encodes for a carbohydrate-specific outer membrane porin [15].
• Resistance to trimethoprim in both cell types arose from a single point mutation in folA (Ile94-->Leu) and cefotaxime resistance resulted from loss of outer membrane porin OmpF [16].

Anatomical context of ompG

• Reconstitution experiments with lipid bilayer membranes defined BglH as a channel-forming component, i.e. it is an outer membrane porin [15].
• In contrast, most (55%) of a pullulanase variant with an aspartate at position +2 cofractionated with slightly lighter fractions that contained small proportions of both outer membrane porin and the cytoplasmic membrane marker NADH oxidase [17].

Associations of ompG with chemical compounds

• A non-secretable pullulanase variant with a serine at position +2 cofractionated mainly with the major peak of outer membrane porin [17].
• The second mutation, nfxB, mapped between 20 and 22 min was associated with additional resistances to tetracycline, chloramphenicol, and cefoxitin and with decreases in outer membrane porin protein OmpF [18].
• We conclude that the maltose-binding protein does not modulate the activity of maltoporin as a general outer membrane porin [19].
• It exhibited constitutive glycerol-3-phosphate transport activity and synthesized a new outer membrane porin [20].

Regulatory relationships of ompG

• As a result of this 13.1-kb deletion, the expression of ompG was placed under the control of the pspA promoter [1].
• The Rob-induced antibiotic resistance depended only partially on the micF antisense RNA that down-regulates the OmpF outer membrane porin to limit antibiotic uptake [21].

Other interactions of ompG

• By inserting XbaI octamer linkers into the cloned ompB locus, four distinct frameshift mutants were isolated and subsequently characterized for their OmpR and EnvZ protein products and their outer membrane porin phenotype [22].
• OmpR is a transcriptional activator for the expression of outer membrane porin genes ompF and ompC in Escherichia coli [23].
• When this method was used to clone two chromosomal mutations in the envZ gene of Escherichia coli, a locus which encodes a membrane-bound sensory protein involved in the osmoregulation of outer membrane porin biosynthesis, more than 50% of the retransformants from the plasmids selected by size were found to exhibit the mutant phenotype [24].
• Each monomer of the trimeric outer membrane porin PhoE of Escherichia coli consists of a 16-stranded beta-barrel with short turns at the periplasmic side and large loops at the cell surface [25].

Analytical, diagnostic and therapeutic context of ompG

• Site-directed mutagenesis was performed with the phosphate starvation-inducible outer membrane porin PhoE of Escherichia coli K-12 to study the molecular basis of its anion selectivity [9].
• Crystallization and preliminary X-ray diffraction analysis of ScrY, a specific bacterial outer membrane porin [11].
• Role of the constriction loop in the gating of outer membrane porin PhoE of Escherichia coli [26].

References