Disease relevance of osmY

• A genetic fusion to osmY was mapped to 99.3 min on the E. coli chromosome [1].
• Inactivation of FhuA at the cell surface of Escherichia coli K-12 by a phage T5 lipoprotein at the periplasmic face of the outer membrane [2].
• The lnt gene in a mutant of Salmonella enterica displaying thermosensitive Lnt activity (Gupta, S. D., Gan, K., Schmid, M. B., and Wu, H. C. (1993) J. Biol. Chem. 268, 16551-16556) was found to carry a mutation causing a single glutamate to lysine substitution at a highly conserved position in the last predicted periplasmic loop of the protein [3].
• Any defect in the Tol-Pal proteins or in the major lipoprotein (Lpp) results in the loss of outer membrane integrity giving hypersensitivity to drugs and detergents, periplasmic leakage and outer membrane vesicle formation [4].
• The deduced amino acid sequence of an open reading frame (ORF1) located downstream from IRP1 was homologous with a family of periplasmic proteins involved in iron transport in gram-negative bacteria and with the ferrichrome receptor, FhuD, from Bacillus subtilis [5].

Psychiatry related information on osmY

• Since intrinsic resistance involves the collaboration of restricted outer membrane permeability and secondary defense mechanisms, such as periplasmic beta-lactamase (which H. pylori lacks) or efflux, we examined the possible role of efflux in antibiotic susceptibility [6].

High impact information on osmY

• E. coli, and other gram negative microorganisms, contain a periplasmic Cu, ZnSOD that may serve to protect against extracellular O2-. Mn(III) complexes of multidentate macrocyclic nitrogenous ligands catalyze the dismutation of O2- and are being explored as potential pharmaceutical agents [7].
• Oxidation of cysteine pairs to disulfide requires cellular factors present in the bacterial periplasmic space [8].
• DsbB is an E. coli membrane protein that oxidizes DsbA, a periplasmic dithiol oxidase [8].
• These are propagated and amplified across the plug, eventually resulting in substantially different protein conformations at the periplasmic face [9].
• Protease and biotinylation accessibility studies of right side-out and inside-out membrane vesicles derived from this strain revealed that SecA was exposed to the periplasmic surface of the inner membrane [10].

Chemical compound and disease context of osmY

• Cationic antimicrobial peptides, such as polymyxin and cecropin, activated transcription of osmY and micF in growing Escherichia coli independently of each other [11].
• The periplasmic acid glucose-1-phosphatase (G-1-Pase) encoded by gene agp is necessary for the growth of Escherichia coli in a minimal medium containing glucose-1-phosphate (G-1-P) as the sole source of carbon [12].
• Purification of the precursor form of maltose-binding protein, a periplasmic protein of Escherichia coli [13].
• Cationic antimicrobial peptides, such as polymyxin B (PxB), below growth inhibitory concentration induce expression of osmY gene in viable E. coli without leakage of solutes and protons. osmY expression is also a locus of hyperosmotic stress response induced by common food preservatives, such as hypertonic NaCl or sucrose [14].
• Lipoproteins in Escherichia coli are anchored to the periplasmic side of either the inner or the outer membrane by a lipid moiety that is covalently attached to the amino-terminal cysteine residue [15].

Biological context of osmY

• Forty-eight independent gene fusions were identified, including several in well-characterized RpoS-regulated genes, such as osmY, katE, and otsA [16].
• We demonstrate here that osmY expression is regulated at the level of transcription and that transcription initiates 242 nucleotides upstream of the osmY open reading frame [17].
• 5' and 3' deletions that extended past the transcriptional start region essentially abolished osmY expression, suggesting that there is a single promoter region [17].
• MicF and osmY gene products are associated with membrane functions and are responsive to oxidative stress [18].
• We show the osmotically regulated synthesis of a 32 kDa periplasmic protein that is a glycine betaine binding protein with a KD of 1.4 microM [19].

Anatomical context of osmY

• The simplest explanation for these results and those of pulse-chase experiments is that specific sites in the cytoplasmic membrane become progressively occupied by the hybrid protein, resulting in an inhibition of normal localization and processing of periplasmic and outer-membrane proteins [20].
• In this study, we show that depletion of the periplasmic contents of the cell by spheroplast formation does indeed lead to induction of the Cpx envelope stress response [21].
• The periplasmic dipeptide-binding protein (DBP), encoded by the dppA gene, also serves as a chemoreceptor [22].
• By the same genetic screens, we characterized loop-variant MBPs associated with a defective periplasmic folding pathway and aggregated into inclusion bodies [23].
• Six contingent aromatic residues line the channel and form a path from the vestibule to the periplasmic outlet [24].

Associations of osmY with chemical compounds

• One of these mutations conferred glucose sensitivity and was localized in pgi (encoding phosphoglucose isomerase). pgi::Tn10 strains exhibit increased basal levels of expression of osmY and otsBA in exponentially growing cells and reduced osmotic inducibility of these genes [25].
• We therefore propose that the cellular content of UDP-glucose serves as an internal signal that controls expression of osmY and other sigma S-dependent genes [25].
• Conversely, replacement of -35 site cytosine nucleotides with thymidine in the sigma S-dependent osmY promoter reduced transcription by E sigma S and increased transcription by E sigma D. Our data suggest that DNA sequences in the -35 region function as part of a discriminator mechanism to shift transcription between E sigma D and E sigma S [26].
• Starting from a soluble cell extract of this strain, the precursor form of the maltose-binding protein, a periplasmic protein, was purified to homogeneity [13].
• Using polyacrylamide gel electrophoresis, we found a protein of molecular weight 58,000 among the periplasmic proteins of the pTRE5-carrying strain that was absent in UE5 [27].

Other interactions of osmY

• We cloned the chiA (yheB) gene and demonstrated that it codes for a 94.5 kDa periplasmic protein with endochitinase/lysozyme activity [28].
• A chromosomal transcriptional lacZ fusion (csi-5::lacZ) was used to study the regulation of osmY [29].
• The most consistently activated E. coli promoters were those for genes micF, osmY, and dinD [18].
• The mRNA levels of the rpoS and osmY stress genes drastically decrease after induction of the strong overexpression system [30].
• 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) [31].

Analytical, diagnostic and therapeutic context of osmY

• By subcellular fractionation and quantitation with rocket immunoelectrophoresis, we showed that the enzyme was principally localized in the periplasmic fraction [32].
• Cecropin A and B, below or near their minimum inhibitory concentrations in viable Escherichia coli, interfered with the rapid NaCl-induced hyperosmotic shrinkage of the cytoplasmic volume (plasmolysis), and also activated the promoter of the hyperosmotic stress gene osmY [33].
• Like other bacterial transducers, Tsr spans the cytoplasmic membrane twice, forming a periplasmic domain of about 150 amino acids and a cytoplasmic domain of about 300 amino acids [34].
• Escherichia coli thioesterase I, molecular cloning and sequencing of the structural gene and identification as a periplasmic enzyme [35].
• The hydrophobic central domain and both of the periplasmic globular domains each have a pair of highly conserved cysteine residues, and it was shown by site directed mutagenesis that all six conserved cysteine residues contribute to DipZ function [36].

References