Disease relevance of osmB

• Transcription in vitro of two osmoregulated promoters, for the Escherichia coli osmB and osmY genes, was analysed using two species of RNA polymerase holoenzyme reconstituted from purified core enzyme and either sigma D (sigma 70, the major sigma in exponentially growing cells) or sigma S (sigma 38, the principal sigma at stationary growth phase) [1].
• Inactivation of phage T5 by lysed cells after phage multiplication is prevented by a phage-encoded lipoprotein (Llp) that inactivates the FhuA outer membrane receptor protein (K. Decker, V. Krauel, A. Meesmann, and K. Heller, Mol. Microbiol. 12:321-332, 1994) [2].
• Structural evidence that the 32-kilodalton lipoprotein (Tp32) of Treponema pallidum is an L-methionine-binding protein [3].
• The immunodominant 38-kDa lipoprotein antigen of Mycobacterium tuberculosis is a phosphate-binding protein [4].
• The OprM lipoprotein of Pseudomonas aeruginosa is a member of the MexAB-OprM xenobiotic-antibiotic transporter subunits that is assumed to serve as the drug discharge duct across the outer membrane [5].

High impact information on osmB

• This recognition mechanism provides the basis for regulation of protein transport from the TGN to endosomes/lysosomes, which is shared by sortilin and low-density lipoprotein receptor-related protein [6].
• Selection of multicopy suppressors of the temperature-sensitive phenotype of cells lacking sigmaE revealed that overexpression of the lipoprotein NlpE restored high temperature growth to these cells [7].
• Human serum albumin, high density and low density lipoprotein, and IgG together protect erythrocytes and platelets against attack by even high doses (5-25 micrograms/ml) of ECH [8].
• Spleen cells from these mice were unresponsive to a series of B-cell mitogens including LPS prepared from Escherichia coli K235 and from E. coli 0111:B4, lipoprotein mitogen from E. coli, and Nocardia water-soluble mitogen (NWSM) [9].
• A complex of structures including the Ig-receptor molecules, the LPS receptor, and the lipoprotein receptor appear involved in the regulation of mitogenic stimulation of B cells to proliferation and differentiation to IgM-secreting cells [10].

Chemical compound and disease context of osmB

• Escherichia coli carrying the cloned gene produced the predicted hybrid protein that is the same as the major lipoprotein except that the diacyl glycerylcysteine residue at the NH2 terminus is replaced by the Ala-Glu residue [11].
• The fact that the material released from E. coli C600 showed a constant ratio of lipoprotein, OmpA, and phosphatidylethanolamine at all EDTA concentrations tested suggests that the material is lost as specific outer membrane patches [12].
• Lipoprotein from the osmoregulated ABC transport system OpuA of Bacillus subtilis: purification of the glycine betaine binding protein and characterization of a functional lipidless mutant [13].
• The Tp38 (TpMglB-2) lipoprotein binds glucose in a manner consistent with receptor function in Treponema pallidum [14].
• The protein is modified with palmitic acid when it is processed in E. coli, confirming that it is a typical lipoprotein [15].

Biological context of osmB

• The nucleotide sequence of a 652-base-pair chromosomal DNA fragment containing the osmB gene was determined [16].
• The osmB gene of Escherichia coli, whose expression is induced by elevated osmolarity, was cloned and physically mapped to a 0.65-kilobase-pair NsiI-HincII DNA fragment at 28 min on E. coli chromosome [16].
• The amino acid sequences of YafY and YfjS, another inner membrane lipoprotein, are highly identical, but overproduction of the latter did not induce degP expression [17].
• The hydrophobic cavity most likely represents the binding site for the lipid moiety of a lipoprotein [18].
• These results most likely suggest that the major lipoprotein exists as a trimer in the periplasmic space with interactions with the peptidoglycan layer through the protein domain on one side and with the outer membrane through the lipid domain on the other side [19].

Anatomical context of osmB

• A novel protein that is essential for the release of Lpp from the inner membrane was discovered in the periplasm and purified [20].
• The major outer membrane lipoprotein (Lpp) expressed in spheroplasts was, however, retained in the inner membrane as a mature form [20].
• The apo-form of peptidoglycan-anchored major lipoprotein (Lpp) and two other outer membrane lipoproteins accumulated in the plasma membrane when lnt expression was reduced [21].
• The hybrid genes were preceded by a ribosome binding site (RBS) and were expressed under transcriptional control of both the lipoprotein promoter (Plpp) and the lac promoter-operator (POlac) [22].
• Anti-immunoglobulin antibodies inhibit the mitogenic stimulation of B cells by lipoprotein [10].

Associations of osmB with chemical compounds

• Although a larger part of the protein was extractable with sodium dodecyl sulfate, a part of the hybrid protein was covalently bound to the peptidoglycan layer as the lipoprotein is [19].
• Globomycin inhibited maturation of protein D in H. influenzae, implying that protein D is exported through the lipoprotein export pathway [23].
• The putative mature 341-amino-acid-residue XylF (calculated molecular mass of 37,069 Da) appears to be a lipoprotein attached to the cell membrane via a lipid anchor covalently linked to the N-terminal cysteine, as demonstrated by metabolic labelling of the recombinant XylF with [14C]palmitate [24].
• EDTA treatment induced losses of LPS (up to 40%), outer membrane proteins OmpA, OmpF/C, and lipoprotein, periplasmic proteins, and phosphatidylethanolamine [12].
• The recombinant K4(2) did not bind to either lysine- or proline-Sepharose, suggesting that the ligand binding activities of lipoprotein (a) may reside in the other kringle domains of apolipoprotein (a) [25].

Regulatory relationships of osmB

• On the other hand, new inner membrane lipoprotein YafY strongly induced degP expression irrespective of the mode of fusion even though the level of overproduced YafY was lower than that of NlpE [17].

Other interactions of osmB

• Alteration of the lipoprotein-sorting signals of NlpE and YafY did not abolish the degP induction [17].
• Accordingly, the gene has been named nlpE (for new lipoprotein E) [26].
• The haemolytic activity of E. coli carrying multiple copies of slyA is found mainly in the cytoplasm, with some in the periplasm of cells grown to stationary phase, but overexpression of SlyB, a 15 kDa lipoprotein probably located in the outer membrane, may lead to enhanced, albeit unspecific, release of the haemolytic activity into the medium [27].

Analytical, diagnostic and therapeutic context of osmB

• By site-directed mutagenesis of the 19Ag lipoprotein leader sequence, we have generated a mutant gene which directs the production of 19Ag into the periplasmic space of E. coli, from where it can be easily purified in high yield [28].
• In conclusion, a convenient protein engineering strategy for converting non-lipoprotein to lipoprotein for commercial application has been devised and tested successfully [29].
• Eighteen hours after an intraperitoneal injection of endotoxin, the hepatic LDL-receptor expression and the plasma lipoprotein pattern were analyzed [30].
• We believe that the molecular cloning and characterization of N-SMase cDNA will accelerate the process to define its role as a key regulator in apoptosis, lipid and lipoprotein metabolism, and other cell regulatory pathways [31].
• Immunoblotting analysis using the antibody against the 45-kDa protein revealed a 48-kDa precursor of the protein, which accumulated in the cyanobacterial cells treated with globomycin, an antibiotic that specifically inhibits cleavage of the signal peptide of lipoprotein precursors [32].

References