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J Mol Biol . 2012 Jan 30; Papadakos G, Housden NG, Lilly KJ, Kaminska R, Kleanthous C TolB and Pal are members of the Tol-Pal system that spans the cell envelope of Gram-negative bacteria and contributes to the stability and integrity of the bacterial outer membrane (OM). See the original post here: Nat Rev Microbiol . 2012; 10(3): 213-25 Leyton DL, Rossiter AE, Henderson IR Autotransporters are a superfamily of proteins that use the type V secretion pathway for their delivery to the surface of Gram-negative bacteria. At first glance, autotransporters look to contain all the functional elements required to promote their own secretion: an amino-terminal signal peptide to mediate translocation across the inner membrane, a central passenger domain that is the secreted functional moiety, and a channel-forming carboxyl terminus that facilitates passenger domain translocation across the outer membrane See more here: J Biol Chem . 2012 Feb 3; Xu Y, Moeller A, Jun SY, Lee M, Yoon BY, Kim JS, Lee K, Ha NC Gram-negative bacteria are capable of expelling diverse xenobiotic substances from within the cell by use of three-component efflux pumps in which the energy-activated inner membrane transporter is connected to the outer membrane channel protein via the membrane fusion protein. In this study, we describe the crystal structure of the membrane fusion protein MexA from the Pseudomonas aeruginosa MexAB-OprM pump in the hexameric ring arrangement Excerpt from: Outer membrane proteins of gram-negative bacteria had been proved to be of high immunocompetence to induce strong specific immunoreaction. As the targets for attacking of the immunocytes and antibodies,they can mediate immunoreaction to kill the bacteria more directly,and play an important role in immune protection.Omp 18 and UreB are outer membrane protein of H.pylori,Which encoding gene show highly conservative.But none of the antigens was capable … View original post here:
PLoS One. 2012; 7(1): e30403 The YycFG two-component regulatory system (TCS) of Staphylococcus aureus represents the only essential TCS that is almost ubiquitously distributed in Gram-positive bacteria with a low G+C-content. YycG (WalK/VicK) is a sensor histidine-kinase and YycF (WalR/VicR) is the cognate response regulator. Both proteins play an important role in the biosynthesis of the cell envelope and mutations in these proteins have been involved in development of vancomycin and daptomycin resistance.Here we present high yield expression and purification of the full-length YycG and YycF proteins as well as of the auxiliary proteins YycH and YycI of Staphylococcus aureus. Activity tests of the YycG kinase and a mutated version, that harbours an Y306N exchange in its cytoplasmic PAS domain, in a detergent-micelle-model and a phosholipid-liposome-model showed kinase activity (autophosphorylation and phosphoryl group transfer to YycF) only in the presence of elevated concentrations of alkali salts. A direct comparison of the activity of the kinases in the liposome-model indicated a higher activity of the mutated YycG kinase. Further experiments indicated that YycG responds to fluidity changes in its microenvironment.The combination of high yield expression, purification and activity testing of membrane and membrane-associated proteins provides an excellent experimental basis for further protein-protein interaction studies and for identification of all signals received by the YycFGHI system. Read the original post: PLoS Biol . 2012 Jan; 10(1): e1001242 Eren E, Vijayaraghavan J, Liu J, Cheneke BR, Touw DS, Lepore BW, Indic M, Movileanu L, van den Berg B Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM) that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics The rest is here: Structure . 2012 Jan 11; 20(1): 121-7 Bosshart PD, Iordanov I, Garzon-Coral C, Demange P, Engel A, Milon A, Müller DJ In Klebsiella pneumoniae the transmembrane β-barrel forming outer membrane protein KpOmpA mediates adhesion to a wide range of immune effector cells, thereby promoting respiratory tract and urinary infections. As major transmembrane protein OmpA stabilizes Gram-negative bacteria by anchoring their outer membrane to the peptidoglycan layer. View original post here: Structure . 2012 Jan 11; 20(1): 121-7 Bosshart PD, Iordanov I, Garzon-Coral C, Demange P, Engel A, Milon A, Müller DJ In Klebsiella pneumoniae the transmembrane β-barrel forming outer membrane protein KpOmpA mediates adhesion to a wide range of immune effector cells, thereby promoting respiratory tract and urinary infections. As major transmembrane protein OmpA stabilizes Gram-negative bacteria by anchoring their outer membrane to the peptidoglycan layer Here is the original post: J Biol Chem . 2012 Jan 17; Gu S, Kelly G, Wang X, Frenkiel T, Shevchik VE, Pickersgill RW The type II secretion system of Gram-negative bacteria is important for bacterial pathogenesis and survival; it is composed of 12 core proteins mostly multimeric which build a sophisticated secretion machine spanning both bacterial membranes. OutC (GspC) is the core component of the inner-membrane sub-complex, thought to be involved in both recognition of substrate and interaction with the outer-membrane secretin, OutD (GspD). More here:
Cell Microbiol. 2012 Jan 10; Chlamydia spp. are obligate intracellular bacteria that replicate inside the host cell in a bacterial-modified-unique compartment called the inclusion. As other intracellular pathogens, chlamydiae exploit host membrane trafficking pathways to prevent lysosomal fusion and to acquire energy and nutrients essential for their survival and replication. The Conserved Oligomeric Golgi (COG) complex is a ubiquitously expressed membrane-associated protein complex that functions in a retrograde intra-Golgi trafficking through associations with coiled-coil tethers, SNAREs, Rabs and COPI proteins. Several COG complex-interacting proteins, including Rab1, Rab6, Rab14 and Syntaxin 6 are implicated in chlamydial development. In this study, we analyzed the recruitment of the COG complex and GS15-positive COG complex-dependent (CCD) vesicles to Chlamydia trachomatis inclusion and their participation in chlamydial growth. Immunofluorescent analysis revealed that both GFP-tagged and endogenous COG complex subunits associated with inclusions in a serovar-independent manner by 8 h post infection and were maintained throughout the entire developmental cycle. Golgi v-SNARE GS15 was associated with inclusions 24 h post infection, but was absent on the mid-cycle (8 h) inclusions, indicating that this Golgi SNARE is directed to inclusions after COG complex recruitment. Silencing of COG8 and GS15 by siRNA significantly decreased infectious yield of chlamydiae. Further, membranous structures likely derived from lysed bacteria were observed inside inclusions by electron microscopy, in cells depleted of COG8 or GS15. Our results showed that C. trachomatis hijacks the COG complex to re-direct the population of Golgi-derived retrograde vesicles to inclusions. These vesicles likely deliver nutrients that are required for bacterial development and replication. Continued here:
Cell Microbiol. 2012 Jan 10; Chlamydia spp. are obligate intracellular bacteria that replicate inside the host cell in a bacterial-modified-unique compartment called the inclusion. As other intracellular pathogens, chlamydiae exploit host membrane trafficking pathways to prevent lysosomal fusion and to acquire energy and nutrients essential for their survival and replication. The Conserved Oligomeric Golgi (COG) complex is a ubiquitously expressed membrane-associated protein complex that functions in a retrograde intra-Golgi trafficking through associations with coiled-coil tethers, SNAREs, Rabs and COPI proteins. Several COG complex-interacting proteins, including Rab1, Rab6, Rab14 and Syntaxin 6 are implicated in chlamydial development. In this study, we analyzed the recruitment of the COG complex and GS15-positive COG complex-dependent (CCD) vesicles to Chlamydia trachomatis inclusion and their participation in chlamydial growth. Immunofluorescent analysis revealed that both GFP-tagged and endogenous COG complex subunits associated with inclusions in a serovar-independent manner by 8 h post infection and were maintained throughout the entire developmental cycle. Golgi v-SNARE GS15 was associated with inclusions 24 h post infection, but was absent on the mid-cycle (8 h) inclusions, indicating that this Golgi SNARE is directed to inclusions after COG complex recruitment. Silencing of COG8 and GS15 by siRNA significantly decreased infectious yield of chlamydiae. Further, membranous structures likely derived from lysed bacteria were observed inside inclusions by electron microscopy, in cells depleted of COG8 or GS15. Our results showed that C. trachomatis hijacks the COG complex to re-direct the population of Golgi-derived retrograde vesicles to inclusions. These vesicles likely deliver nutrients that are required for bacterial development and replication. Originally posted here: Immunity . 2011 Dec 23; 35(6): 997-1009 Chen K, McAleer JP, Lin Y, Paterson DL, Zheng M, Alcorn JF, Weaver CT, Kolls JK The interleukin-17 (IL-17) family of cytokines phylogenetically predates the evolution of T cells in jawed vertebrates, suggesting that the ontogeny of the Th17 cell lineage must have arisen to confer an evolutionary advantage to the host over innate sources of IL-17. Utilizing a model of mucosal immunization with the encapsulated bacteria Klebsiella pneumoniae, we found that B cells, which largely recognized polysaccharide capsular antigens, afforded protection to only the vaccine strain. Go here to see the original: Microb Pathog . 2011 Dec 13; Vilches S, Jiménez N, Merino S, Tomás JM Pathogenesis of Aeromonas species have been reported to be associated with virulence factors such as lipopolysaccharides (LPS), bacterial toxins, bacterial secretion systems, flagella, and other surface molecules. Read more here: |
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