Title: Nucleic Acid Sequence Based Amplification (NASBA) of Chlamydia pneumoniae Major Outer Membrane Protein (ompA) mRNA with Bioluminescent Detection. VOLUME: 3 ISSUE: 4. Author(s):B. K. Coombes and J. B. Mahony. Affiliation:Regional Virology and Chlamydiology Laboratory, St. Josephs Hospital, 50 Charlton Ave. East,Hamilton, Ontario, L8N 4A6, CANADA.. Abstract: Chlamydia pneumoniae has been associated with chronic conditions such as atherosclerosis and coronary heart disease but the precise role of this intracellular bacteria in the pathogenesis of these diseases is not well defined. Several techniques have been developed for detection of C. pneumoniae in atheromatous lesions, however it remains unclear whether persistent forms of the organism and/or actively replicating bacteria contribute to associated pathology. The aim of this study was to utilize nucleic acid sequence based amplification (NASBA) technology together with a highly sensitive aequorin bioluminescent hybridization assay for ...
Journal Article: Small-Molecule Transport by CarO, an Abundant Eight-Stranded beta-Barrel Outer Membrane Protein from Acinetobacter Baumannii ...
TY - JOUR. T1 - A set of two monoclonal antibodies specific for the cell surface-exposed 39K major outer membrane protein of Haemophilus influenzae type b defines all strains of this pathogen. AU - Gulig, P. A.. AU - Frisch, C. F.. AU - Hansen, E. J.. PY - 1983. Y1 - 1983. N2 - Six murine plasma cell hybridomas producing monoclonal antibodies (mabs) directed against the 39,000-molecular-weight (39K) major outer membrane protein of Haemophilus influenzae type b were employed in the antigenic analysis of the 39K protein. The initial characterization of the mabs by radioimmunoprecipitation analysis showed that four of these mabs reacted with antigenic determinants of the 39K protein that are exposed on the bacterial cell surface and accessible to antibody. The other two mabs reacted with antigenic determinants of the 39K protein that are either not exposed on the H. influenzae type b cell surface or not accessible to antibody (internal determinants). A total of 126 clinical isolates of H. ...
Outer membrane proteins are structurally distinct from those that reside in the inner membrane and play important roles in bacterial pathogenicity and human metabolism. X-ray crystallography studies on |40 different outer membrane proteins have revealed that the transmembrane portion of these proteins can be constructed from either beta-sheets or less commonly from alpha-helices. The most common architecture is the beta-barrel, which can be formed from either a single anti-parallel sheet, fused at both ends to form a barrel or from multiple peptide chains. Outer membrane proteins exhibit considerable rigidity and stability, making their study through x-ray crystallography particularly tractable. As the number of structures of outer membrane proteins increases a more rational approach to their crystallization can be made. Herein we analyse the crystallization data from 53 outer membrane proteins and compare the results to those obtained for inner membrane proteins. A targeted sparse matrix screen for
OprF is a major outer membrane protein from Pseudomonas aeruginosa, a homolog of OmpA from Escherichia coli. The N-terminal domains of both proteins have been demonstrated to form low conductance channels in lipid bilayers. Homology models, consisting of an eight-stranded beta-barrel, of the N-terminal domain OprF have been constructed based on the crystal structure of the corresponding domain from E. coli OmpA. OprF homology models have been evaluated via a set (6 x 10 ns) of simulations of the beta-barrel embedded within a solvated dimyristoyl-phosphatidylcholine (DMPC) bilayer. The conformational stability of the models is similar to that of the crystal structure of OmpA in comparable simulations. There is a degree of water penetration into the pore-like center of the OprF barrel. The presence of an acidic/basic (E8/K121) side-chain interaction within the OprF barrel may form a gate able to close/open a central pore. Lipid-protein interactions within the simulations were analyzed and revealed that
A vast number of studies have been completed on the virulence determinants of Yersinia spp.; however, the focus of many of these studies has been on the virulence plasmid and the plasmid-encoded Type three secretion system. Nevertheless, many chromosomal genes whose products are directly involved in virulence have also been identified. Some of these critical virulence determinants are outer membrane proteins. Outer membrane proteins of Gram-negative bacteria often have important physiological roles; however, some have also been found to be important for pathogenesis. In this thesis, we investigated two Yersinia. pestis outer membrane proteins, Ail and OmpA, and their roles in virulence. We provide evidence that Y. pestis Ail is a highly expressed outer membrane protein that is absolutely essential for Y. pestis to resist the killing action of the complement system present in human blood and tissues, as well as the blood and tissues of other mammalian hosts. Furthermore, Ail was important for ...
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The toxR gene of Vibrio cholerae encodes a transmembrane, DNA-binding protein that activates transcription of the cholera toxin operon and a gene (tcpA) for the major subunit of a pilus colonization factor. We constructed site-directed insertion mutations in the toxR gene by a novel method employing the chromosomal integration of a mobilizable suicide plasmid containing a portion of the toxR coding sequence. Mutants containing these new toxR alleles had an altered outer membrane protein profile, suggesting that two major outer membrane proteins (OmpT and OmpU) might be under the control of toxR. Physiological studies indicated that varying the concentration of the amino acids asparagine, arginine, glutamate, and serine caused coordinate changes in the expression of cholera toxin, TcpA, OmpT, and OmpU. Changes in the osmolarity of a tryptone-based medium also produced coordinate changes in the expression of these proteins. Other environmental signals (temperature and pH) had a more pronounced ...
Drugs and certain proteins are transported across the membranes of Gram-negative bacteria by energy-activated pumps. The outer membrane component of these pumps is a channel that opens from a sealed resting state during the transport process. We describe two crystal structures of the Escherichia coli outer membrane protein TolC in its partially open state. Opening is accompanied by the exposure of three shallow intraprotomer grooves in the TolC trimer, where our mutagenesis data identify a contact point with the periplasmic component of a drug efflux pump, AcrA. We suggest that the assembly of multidrug efflux pumps is accompanied by induced fit of TolC driven mainly by accommodation of the periplasmic component.,br/, ...
Cloning and characterization of the major outer membrane protein gene (ompH) of Pasteurella multocida X-73.: The major outer membrane protein (OmpH) of Pasteure
PCR methods.Holland et al. (31) developed a major outer membrane protein (MOMP)-based PCR test that could identify three species of Chlamydia (C. trachomatis, C. pneumoniae, and C. psittaci) using three primer pairs and one restriction enzyme digestion.. Rasmussen et al. (73) described a protocol that amplifies a conserved genus-specific target of the chlamydial MOMP gene followed by restriction enzyme digestion for species identification.. Watson et al. (89) developed a PCR assay based on amplification of the 60-kDa cysteine-rich outer membrane protein genes of C. psittaci, C. pneumoniae, and C. trachomatis, followed by species differentiation with four restriction endonuclease digestion enzymes. Similarly, Tjhie et al. (84) developed a general PCR with a target within the MOMP gene. Subsequent species-specific differentiation of C. trachomatis, C. pneumoniae, and C. psittaciwas performed by hybridization of the amplified PCR product with internal probes.. Several of the early methods described ...
Molecular dynamics simulations by Department of Biochemistrys Dr Phillip Stansfeld, in the lab of Professor Mark Sansom, have helped to reveal how bacteria construct a barrier against antibiotics and the bodys immune system.
Khandelwal and colleagues succeeded in identifying the insecticidal factor. The active component was found in a large complex normally associated with the bacterial outer membrane, and was also present in or on outer membrane vesicles (OMVs) released from the bacterial surface, says Khandelwal. They then searched through OMV components and identified a small (17 kDa) toxic protein. When purified, this protein was toxic to cultured larval cells and directly killed H. armigera larvae. Gene cloning and sequencing showed this protein is related to a class of bacterial outer membrane proteins that form protrusions, called pili or fimbriae, which often help bacteria attach to host cells during infection. Similar to pili proteins, the purified 17 kDa protein self-associated to form oligomers, each of which was connected to the next by a strand. Most importantly, the recombinant 17 kDa protein killed H. armigera larvae, demonstrating its potential as a biological control agent in a world desperately in ...
Dispensable loops shield the functionally-important extracellular loops of the essential Gram-negative bacterial outer membrane protein LptD from antibody interference.
TY - JOUR. T1 - Asymmetric phospholipid. T2 - Lipopolysaccharide bilayers; a Gram-negative bacterial outer membrane mimic. AU - Clifton, Luke A.. AU - Skoda, Maximilian W. A.. AU - Daulton, Emma L.. AU - Hughes, Arwel V.. AU - Le Brun, Anton P.. AU - Lakey, Jeremy. H.. AU - Holt, Stephen A.. PY - 2013/12/6. Y1 - 2013/12/6. N2 - The Gram-negative bacterial outer membrane (OM) is a complex and highly asymmetric biological barrier but the small size of bacteria has hindered advances in in vivo examination of membrane dynamics. Thus, model OMs, amenable to physical study, are important sources of data. Here, we present data from asymmetric bilayers which emulate the OM and are formed by a simple two-step approach. The bilayers were deposited on an SiO2 surface by Langmuir-Blodgett deposition of phosphatidylcholine as the inner leaflet and, via Langmuir-Schaefer deposition, an outer leaflet of either Lipid A or Escherichia coli rough lipopolysaccharides (LPS). The membranes were examined using ...
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class=publication>Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href=http://www.nrbook.com/b/bookcpdf.php>Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
TY - JOUR. T1 - Studies on the region involved in the transport activity of Escherichia coli TolC by chimeric protein analysis. AU - Yamanaka, Hiroyasu. AU - Tadokoro, Satoshi. AU - Miyano, Masaya. AU - Takahashi, Eizo. AU - Kobayashi, Hidetomo. AU - Okamoto, Keinosuke. N1 - Funding Information: This study was supported in part by a grant-in-aid for scientific research (C) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Grant no. 14570252) and the scientific grant 2006 from Hiroshima International University, Japan (Project no. 9905833).. PY - 2007/5. Y1 - 2007/5. N2 - Gram-negative bacteria possess the outer membrane protein TolC which acts as an exit duct across the outer membrane. However, the region involved in the transport activity of TolC has remained unclear. We analyzed this region by creating chimeric TolCs. First, we expressed the genes for TolCs of Vibrio parahaemolyticus (vp-tolC) and Salmonella typhimurium (sal-tolC) in Escherichia coli. The levels ...
Bacterial OMPs are synthesized in the cytosol as precursor proteins with an amino‐terminal signal sequence that guides the proteins to the Sec machinery for crossing the inner membrane and is cleaved off in the periplasm. Periplasmic chaperones then escort OMPs through the aqueous periplasmic space in a partly unfolded state. On reaching the outer membrane, OMPs assemble into a β‐barrel structure and insert into the outer membrane with the help of the BAM complex. The bacterial OMP insertion pathway can be compared to the assembly pathway of MBOMPs from the mitochondrial intermembrane space into the outer membrane. MBOMPs are synthesized in the cytosol and imported into the intermembrane space by the outer membrane translocator TOM40. The subsequent chaperone‐mediated escort across the intermembrane space and insertion into the outer membrane by the TOB complex is similar to the OMP assembly process. Notably, the BAM and TOB complexes share the homologous β‐barrel proteins BamA and ...
Tohidi, F. and Teymournejad, O. and Taravati, A. and Al Ahmadi, K. J. and Rajabnia, R. (2015) Analysis of important H.pylori Outer membrane proteins by detection of common sequences in exposed areas; in silico study. Biosciences Biotechnology Research Asia, 12. pp. 135-143. Tohidi, F. and Teymournejad, O. and Taravati, A. and Al Ahmadi, K. J. and Rajabnia, R. (2015) Analysis of important H.pylori Outer membrane proteins by detection of common sequences in exposed areas; in silico study. Biosciences Biotechnology Research Asia, 12. pp. 135-143. ...
Antigen 43 is a unique autotransporter that promote bacterial cell-to-cell aggregation. Antigen 43 can be expressed on the E.coli cell surface in large quantities, up to 50000 copies per cell.[1] The structure analysis of antigen 43 revealed that antigen 43 has an N-terminal signal peptide; an N-proximal passenger domain that is secreted, which could also be called α domain; an autochaperone domain that facilitates folding of the passenger domain; and a C-terminal β-barrel domain that forms an integral outer membrane protein, also called β domain[2]. The passenger domain(αdomain) confers the autoaggregation phenotype and it is bound to the surface via non-covalent interaction with the βdomain. ...
Proteins can be immobilised on surfaces to make arrays with potential uses in tissue engineering, proteomics and point of use diagnostic devices. Outer membrane proteins (OMP) from Escherichia coli have a beta-barrel structure, making ideal protein engineering scaffolds for building arrays. The proteins can be immobilised onto flat gold surfaces by introducing a cysteine residue into their periplasmic turns. The thiol group of the cysteine will form a strong gold-thiolate bond immobilising the OMP to the surface in a specific and correct orientation. The membrane layer is completed by the immobilisatin of a lipid with a thiol head group to the gold surface. Here we use the transmembrane section of the monomeric protein OmpA (TmOmpA). The Z domain of Staphylococcus aureau protein A has been engineered into the N - terminal of a circularly permuted TmOmpA to create the protein ZZctOmpA. The Z domain can bind immunoglobulin G (IgG) at its constant region leaving the variable regions free to bind ...
The gram-negative bacterial envelope is a complex extracytoplasmic compartment responsible for numerous cellular processes. Among its most important functions is its service as the protective layer separating the cytoplasmic space from the ever-changing external environment. To adapt to the diverse conditions encountered both in the environment and within the mammalian host, Escherichia coli and Salmonella species have evolved six independent envelope stress response systems . This review reviews the sE response, the CpxAR and BaeSR two-component systems (TCS) , the phage shock protein response, and the Rcs phosphorelay system. These five signal transduction pathways represent the most studied of the six known stress responses. The signal for adhesion to abiotic surfaces enters the pathway through the novel outer membrane lipoprotein NlpE, and activation on entry into the exponential phase of growth occurs independently of CpxA . Adhesion could disrupt NlpE causing unfolding of its unstable N-terminal
Author: Anbazhagan, V. et al.; Genre: Journal Article; Published in Print: 2008-06-10; Title: Incorporation of outer membrane protein OmpG in lipid membranes: protein−lipid interactions and β-barrel orientation.
Allison, Heather, Smith, Darren, Loughnane, Paul, Saunders, Jon and McCarthy, Alan (2004) Identification of an outer membrane protein that enables infection of Escherichia coli by Shiga toxin encoding bacteriophage. In: 155th Society for General Microbiology Meeting, September 2004, Dublin, Ireland. Full text not available from this repository. (Request a copy ...
Danese, P.L., Pratt, L.A., Dove, S.L. and Kolter, R. (2000) The Outer Membrane Protein, Antigen 43, Mediates Cell-to-Cell Interactions within Escherichia coli Biofilms. Molecular Microbiology, 37, 424-432.
Download Free Full-Text of an article EXTRACTION OF THE OUTER MEMBRANE PROTEINS OF H. PYLORI AND EVALUATION OF THEIR PRESENCE IN STOOL OF THE INFECTED INDIVIDUALS
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We compare several spectral domain based clustering methods for partitioning protein sequence data. The main instrument for this exercise is the spectral density ratio model, which specifies that the logarithmic ratio of two or more unknown spectral density functions has a parametric linear combination of cosines. Maximum likelihood inference is worked out in detail and it is shown that its output yields several distance measures among independent stationary time series. These similarity indices are suitable for clustering time series data based on their second order properties. Other spectral domain based distances are investigated as well; and we compare all methods and distances to the problem of producing segmentations of bacterial outer membrane proteins consistent with their transmembrane topology. Protein sequences are transformed to time series data by employing numerical scales of physicochemical parameters. We also present interesting results on the prediction of transmembrane ...
Subunit Of Both The ERMES And The SAM Complex; Component Of ERMES Complex Which Acts As A Molecular Tether Between The Mitochondria And The ER, Necessary For Efficient Phospholipid Exchange Between Organelles And For Mitophagy; SAM/TOB Complex Component That Functions In The Assembly Of Outer Membrane Beta-barrel Proteins; Involved In Mitochondrial Inheritance And Morphology; ERMES Complex Is Often Co-localized With Peroxisomes And Concentrated Areas Of Pyruvate Dehydrogenase
The mitochondrial outer membrane plays a crucial role in the biogenesis, inheritance and dynamics of the organelle and forms the functional and signaling link between mitochondria and the rest of the eukaryotic cell. This membrane contains a diverse set of proteins that are synthesized in the cytosol and harbor signals that are essential for their subsequent import into mitochondria. We investigate the molecular mechanisms by which the various mitochondrial outer membrane proteins are targeted to mitochondria, inserted into the outer membrane and assembled into functional complexes within the membrane. In addition, we study the mechanisms and components that regulate lipids homeostasis in mitochondria. For our studies we use both yeast and mammalian tissue cultures as experimental systems.. ...
The mitochondrial outer membrane plays a crucial role in the biogenesis, inheritance and dynamics of the organelle and forms the functional and signaling link between mitochondria and the rest of the eukaryotic cell. This membrane contains a diverse set of proteins that are synthesized in the cytosol and harbor signals that are essential for their subsequent import into mitochondria. We investigate the molecular mechanisms by which the various mitochondrial outer membrane proteins are targeted to mitochondria, inserted into the outer membrane and assembled into functional complexes within the membrane. In addition, we study the mechanisms and components that regulate lipids homeostasis in mitochondria. For our studies we use both yeast and mammalian tissue cultures as experimental systems.. ...
Nair, S A and Rathinavelan, Thenmalarchelvi (2015) Bidirectional water conductivity of E.coli outer membrane lectin(Wzi) is regulated by surface aromatic residues and luminal hydrophobic plug. In: National Symposium on Biophysics and Golden Jubilee Meeting of Indian Biophysical Society, Center for Interdisciplinary Research in Basic Sciences, 14-17 February 2015, New Delhi, India. Full text not available from this repository. (Request a copy ...
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Bacterial proteins with MCE domains were first described as being important for Mammalian Cell Entry. More recent evidence suggests they are components of lipid ABC transporters. In Escherichia coli, the single-domain protein MlaD is known to be part of an inner membrane transporter that is important for maintenance of outer membrane lipid asymmetry. Here we describe two multi MCE domain-containing proteins in Escherichia coli, PqiB and YebT, the latter of which is an orthologue of MAM-7 that was previously reported to be an outer membrane protein. We show that all three MCE domain-containing proteins localise to the inner membrane. Bioinformatic analyses revealed that MCE domains are widely distributed across bacterial phyla but multi MCE domain-containing proteins evolved in Proteobacteria from single-domain proteins. Mutants defective in mlaD, pqiAB and yebST were shown to have distinct but partially overlapping phenotypes, but the primary functions of PqiB and YebT differ from MlaD. Complementing
Syma Khalid (Investigator) Many bacteria have an outer membrane which is the interface between the cell and its environment. The components of this membrane are well studied at an individual level, but there is a need to model and understand the outer membrane as a whole. In this project we aim to develop such a model of a bacterial outer membrane, linking computer simulations of the component molecules through to a more systems biology approach to modelling the outer membrane as a whole. Such an approach to modelling an OM must be multi-scale i.e. it must embrace a number of levels ranging from atomistic level modelling of e.g. the component proteins through to higher level agent-based modelling of the interplay of multiple components within the outer membrane as a whole. The different levels of description will be integrated to enable predictive modelling in order to explore the roles of outer membrane changes in e.g. antibiotic resistance.. ...
The relationship between iron acquisition and microbial pathogenesis (1, 38, 51, 84, 104) underscores the importance of the role of TonB in cell envelope physiology. Passage of ferric complexes through the OM requires TonB activity, and one theory of this requirement is that TonB participates in transport energetics by capturing proton motive force from the IM (where its N terminus resides) and distributing it to the OM transporters (14, 23, 76, 82, 95). According to the shuttle model of TonB action, it associates with the IM proteins ExbB and ExbD (42, 56), acquires proton motive force-generated energy by an unknown structural transition, and transmits (15) or physically transports (55, 57) the energy across the periplasm to the OM. The proposed interaction of energized TonB with OM proteins entails recognition of ligand-bound receptors and release of the stored force to them by protein-protein interactions between the C-terminal residues of TonB and the TonB box sequence of the LGP (76, ...
We describe a lesion, lamB701-708, affecting the hydrophilic portion of the lambda receptor signal sequence. The C to A transversion of the sixth codon of the signal sequence changes a positively charged arginine to a neutral serine. The phenotype conferred by this alteration is unique among previously described signal sequence mutations. The results suggest an essential role for the charged amino acids of the hydrophilic segment in the initial interaction between a nascent secreted protein and a membrane export site. The results further suggest that synthesis of lambda receptor is coupled to its export ...
The outer membrane of most Gram-negative bacteria is made up of LPS, and in nearly all bacteria that contain LPS it is essential for the life of the organism. The lipid portion of this molecule, lipid A, also known as endotoxin, is a potent activator of the innate immune response. More than 50 genes are required to synthesize LPS and assemble it at the cell surface. Enormous progress has been made in elucidating the structure and biosynthesis of LPS, but until recently the cellular components required for its transport from its site of synthesis in the inner membrane to its final cellular location at the cell surface remained elusive. Here we describe the identification of a protein complex that functions to assemble LPS at the surface of the cell. This complex contains two proteins: Imp, already identified as an essential outer-membrane protein implicated in LPS assembly; another protein, RlpB, heretofore identified only as a rare lipoprotein. We show that RlpB is also essential for cell viability and
The [email protected] Centre provides a platform for research students to deposit their Ph.D. theses and make it available to the entire scholarly community in open access. Shodhganga Mirror Site ...
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CPn0444 is similar to CT871, CT874, CT413, CT812, CT872, CT414, CT412, CT870, CT869, and CT456. They are predicted outer membrane proteins. CT871 is a predicted pmpG outer membrane protein G. Residues 470-1407 are 28% similar to CT871 ...
22, Table 33. Their outer membrane proteins contain cross- reactive antigens and surface-exposed epitopes that are species specific.
An outer membrane protein T (OmpT) could play a vital role in the pathogenesis of the neonatal meningitis Escherichia coli (NMEC) in human and animals. However, whether ompT plays a role in avian pathogenic E. coli (APEC) infection remains unclear. In this study we evaluated the potential of ompT in APEC pathogenesis. An ompT gene was deleted from APEC mutant strain (TW-XM) was constructed and cha ...
sample_1: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_2: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H]/[L,V,I(delta1)-13CH3], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_3: KpOmpA transmembrane domain, [U-15N; 10% 13C], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_4: KpOmpA transmembrane domain, [U-13C; U-15N; U-2H]/[L,V,I(delta1)-13CH3], 1 mM; DHPC 300 mM; NaH2PO4 20 mM; NaCl 100 mM; H2O 90%; D2O 10%. sample_conditions_1: ionic strength: 0.1 M; pH: 6.5; pressure: 1 atm; temperature: 313 K ...
The 5C outer membrane protein, one of the N. meningitidis class 5 proteins, was preferably expressed in bacteria isolated from the nasopharynx and its role in adhering to the mucosal cells and invading them as well as the development of anti-5C antibodies in healthy carriers was demonstrated.... mehr ...
Michalik, M.; Orwick-Rydmark, M.; Habeck, M.; Alva, V.; Arnold, T.; Linke, D.: An evolutionarily conserved glycine-tyrosine motif forms a folding core in outer membrane proteins. PLoS One 12 (8) (2017 ...
View Notes - cells2 from BIOL 20204 at TCU. II. The Cell- Basic Unit of Life A. Cell or Plasma membrane-found @ outer surface of cell 1. Structure i. Thickness-75 ancryms=3/10,000,000 ii. Fluid
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Antigenic determinants were identified from seven chlamydial major outer membrane proteins by using overlapping hexapeptides and polyclonal antisera. Sixty-one determinants were detected, and 30 were surface exposed on the native organisms. The two negatively charged residues, aspartic acid and glutamic acid, were found most often in determinants. Thirteen antigenic sites were further characterized by alanine substitution. Differences in fine specificities of these linear determinants were observed in alanine substitution profiles. Five determinants had adjacent critical residues, while eight had critical residues alternated with noncritical residues. Complete replacement analysis of two antigenic determinants provided more detailed information for elucidating the structural basis of the specificity of antigen-antibody interaction and suggested a correlation between sequence conservation and tolerance to amino acid substitution for antigenic sites subject to intense immune selection pressure. ...
Acinetobacter baumannii is nowadays a relevant nosocomial pathogen characterized by multidrug resistance (MDR) and concomitant difficulties to treat infections. OmpA is the most abundant A. baumannii outer membrane (OM) protein, and is involved in virulence, host-cell recognition, biofilm formation, regulation of OM stability, permeability and antibiotic resistance. OmpA members are two‐domain proteins with an N‐terminal eight‐stranded β‐barrel domain with four external loops (ELs) interacting with the environment, and a C‐terminal periplasmic domain binding non‐covalently to the peptidoglycan. Here, we combined data from genome sequencing, phylogenetic and multilocus sequence analyses from 975 strains/isolates of the Acinetobacter calcoaceticus/Acinetobacter baumannii complex (ACB), 946 from A. baumannii, to explore ompA microevolutionary divergence. Five major ompA variant groups were identified (V1 to V5) in A. baumannii, encompassing 52 different alleles coding for 23 different ...
A murine immunoglobulin G monoclonal antibody (MAb) raised against outer membrane vesicles of Moraxella catarrhalis 035E was shown to bind to a surface-exposed epitope of a major outer membrane protein of this organism. This outer membrane protein, which had an apparent molecular weight of approximately 80,000 in sodium dodecyl sulfate-polyacrylamide gels, was designated CopB. MAb 10F3, reactive with CopB, bound to a majority (70%) of M. catarrhalis strains tested. More importantly, mice passively immunized with MAb 10F3 exhibited an enhanced ability to clear a bolus challenge of M. catarrhalis from their lungs, a result which suggested that CopB might have potential as a vaccine candidate. The M. catarrhalis gene encoding CopB was cloned in Escherichia coli, and nucleotide sequence analysis of the copB gene indicated that the CopB protein was synthesized with a leader peptide, a finding confirmed by N-terminal amino acid sequence analysis of the mature CopB protein purified from M. catarrhalis ...
The signal peptide of the outer membrane lipoprotein (OMLP) of Escherichia coli was shown to be capable of promoting protein translocation across mammalian microsomal membranes in vitro. We assayed translocation of a fusion protein containing the OMLP signal peptide and nine amino acids of OMLP fused in frame to beta-lactamase. The efficiency with which the mammalian translocation machinery recognizes and accepts the OMLP signal peptide as substrate is indistinguishable from that of mammalian secretory proteins. Upon translocation mammalian signal peptidase processes the pre-OMLP-beta-lactamase protein at different sites than are utilized in vivo by E. coli OMLP signal peptidase (signal peptidase II) but that can be predicted as mammalian signal peptidase cleavage sites. Mutants in the OMLP signal peptide were tested for their ability to promote translocation of the fusion protein in this assay system. It has been shown previously that mutants in the positively charged amino acids at the amino ...
rdf:RDF xmlns:dcterms=http://purl.org/dc/terms/ xmlns:dc=http://purl.org/dc/elements/1.1/ xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns# xmlns:bibo=http://purl.org/ontology/bibo/ xmlns:dspace=http://digital-repositories.org/ontologies/dspace/0.1.0# xmlns:foaf=http://xmlns.com/foaf/0.1/ xmlns:void=http://rdfs.org/ns/void# xmlns:xsd=http://www.w3.org/2001/XMLSchema# , ,rdf:Description rdf:about=https://kops.uni-konstanz.de/rdf/resource/123456789/1275, ,dspace:isPartOfCollection rdf:resource=https://kops.uni-konstanz.de/rdf/resource/123456789/28/, ,dc:creator,Qu, Jian,/dc:creator, ,dc:contributor,Holst, Otto,/dc:contributor, ,foaf:homepage rdf:resource=http://localhost:8080/jspui/, ,dcterms:abstract xml:lang=eng,Periplasmic Skp facilitates folding and membrane insertion of many outer membrane proteins (OMPs) into the outer membrane of Gram-negative bacteria. We have examined the binding sites of outer membrane protein A (OmpA) from Escherichia coli in its complexes ...
Part of the outer membrane protein assembly complex, which is involved in assembly and insertion of beta-barrel proteins into the outer membrane. Constitutes, with BamD, the core component of the assembly machinery.
The availability of genome sequences and the corresponding translated protein databases have enabled studies on the meningococcal proteome, particularly the detailed composition of outer membrane fractions. In early studies, Frasch and colleagues [20] were able to distinguish only five major classes of proteins in outer membrane preparations from meningococci. Subsequently, additional proteins were identified that were present in lower amounts or only expressed when the bacteria had been grown under nutrient limitation (reviewed in [21]). The total number of proteins identified in outer membrane preparations remained relatively few until the development of more sensitive proteomic methods. This combined with the availability of the translated genome sequences has enabled much more detailed study of outer membrane preparations and the vesicle/vaccine preparations derived from them by deoxycholate extraction. One-dimensional SDS-PAGE of an OMV vaccine preparation followed by tandem mass ...
Outer membrane porin D is a protein family containing bacterial outer membrane porins which are involved in transport of cationic amino acids, peptides, antibiotics and other compounds. It was also described as having some serine protease activity. However many of these proteins are not peptidases and are classified as non-peptidase homologues as they either have been found experimentally to be without peptidase activity, or lack amino acid residues that are believed to be essential for the catalytic activity of peptidases in the S43 family. Yoshihara E, Yoneyama H, Ono T, Nakae T (June 1998). Identification of the catalytic triad of the protein D2 protease in Pseudomonas aeruginosa. Biochem. Biophys. Res. Commun. 247 (1): 142-5. doi:10.1006/bbrc.1998.8745. PMID 9636669. This article incorporates text from the public domain Pfam and InterPro ...
No information on the cytokine profile to be used as a marker of Campylobacter jejuni infection protection. For this study, we used the outer membrane protein (MOMP [Pora]) as a vaccine for the protection and spleen cell cytokine as a marker of protection. We cloned and expressed Pora from C. jejuni111 and mice immunized with intraperitoneal route. Subsequently, the mice orally challenged with C. jejuni 111. live vaccine-induced protection as evidenced by a decrease in fecal excretion C. jejuni111. Cytokines were measured in vitro after stimulation of spleen cells with MOMP. Levels of pro-inflammatory cytokines, IL-12, TNF-α, IL-17A and IL-17F are similar in the control and test mice. Levels of pro-inflammatory cytokines, IL-2 and IFN-γ were higher in mice than in control mice test, and the level of pro-inflammatory cytokines, IL-8 and IL-1β was higher in the test mice than in control mice. In between the two anti-inflammatory cytokines, the same level of IL-10 but higher for IL-4 in the test ...
In this study pore forming proteins of the gram-negative bacteria B. burgdorferi, B. duttonii and E.coli were investigated. Therefore the study is subdivided into three parts. In the first part outer membrane preparation of three relapsing fever Borrelia were investigated. In the second part the putative TolC homologue BB0124 of B. burgdorferi, the Lyme borreliosis agent, was studied. In the last part the influence of point mutants within the greasy slide of the maltose specific porin (LamB) of E. coli were shown. In the first part of this study outer membrane preparations of three Borrelia relapsing fever strains have been studied for pore-forming activity in the black lipid bilayer assay. Histograms of conductance fluctuations were obtained from single-channel experiments with outer membrane preparations of B. hermsii, B. recurentis and B. duttonii. All strains had a different conductance fluctuation pattern with a broad range of single-channel conductance values varying from 0.5 nS - 11 nS. ...
The Tar chemoreceptor of Escherichia coli is a membrane-bound sensory protein that facilitates bacterial chemotaxis in response to aspartate. 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. The cytoplasmic signaling domain of Tar was replaced with the carboxyl portion of EnvZ, and the resulting chimeric receptor activated transcription of the ompC gene in response to aspartate. The activation of ompC by the chimeric receptor was absolutely dependent on OmpR, a transcriptional activator for ompF and ompC. ...
Gonorrheal urethritis was induced in three males by intraurethral instillation of predominantly pilus+ protein II- gonococci. Virtually all gonococci reisolated from the infected men exhibited protein II+ phenotype. The reisolated gonococci expressed five distinct outer membrane protein II species. Protein IIc+ organisms predominated in urines of all three subjects, but variants expressing this particular protein II were rarely spawned in vitro by input organisms. Protein IIc+ gonococci appeared early in one mans infection; they were joined later by variants that displayed eight other protein II phenotypes, including protein II-. These results show that input protein II- gonococci are supplanted by protein IIc+ variants during incipient gonorrheal urethritis. As infection progresses, a broader variety of protein II+ variants appears. ...
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PubMed journal article Export of the outer membrane lipoprotein is defective in secD, secE, and secF mutants of Escherichia col were found in PRIME PubMed. Download Prime PubMed App to iPhone or iPad.
Bacteria outer membrane lipoprotein I: vaccine candidate; antigenically cross-reacts with all serotype strains of the International Antigenic Typing Scheme; amino acid sequence given in first source
Lipoprotein NlpI of Escherichia coli is involved in the cell division, virulence, and bacterial interaction with eukaryotic host cells. To elucidate the functional mechanism of NlpI, we examined how NlpI affects cell division and found that induction of NlpI inhibits nucleoid division and halts cell growth. Consistent with these results, the cell division protein FtsZ failed to localize at the septum but diffused in the cytosol. Elevation of NlpI expression enhanced the transcription and the outer membrane localization of the heat shock protein IbpA and IbpB. Deletion of either ibpA or ibpB abolished the effects of NlpI induction, which could be restored by complementation. The C-terminus of NlpI is critical for the enhancement in IbpA and IbpB production, and the N-terminus of NlpI is required for the outer membrane localization of NlpI, IbpA, and IbpB. Furthermore, NlpI physically interacts with IbpB. These results indicate that over-expression of NlpI can interrupt the nucleoids division and the
Genome analysis identified a large number of genes that would enable utilization of dilute carbon sources and provides a comprehensive picture of the strategies used by C. crescentus for survival in nutrient-limiting conditions. Unlike E. coli and Vibrio cholerae, C. crescentus has no OmpF-type outer membrane porins that allow the passive diffusion of hydrophilic substrates across the outer membrane. However, it does possess 65 members of the family of TonB-dependent outer membrane channels that catalyze energy-dependent transport across the outer membrane. This is more than any other organism thus far characterized, with the next highest being 34 in Pseudomonas aeruginosa (32), and with no other sequenced proteobacteria possessing more than 10. C. crescentus has substantially fewer cytoplasmic membrane transporters relative to genome size than either E. coli or V. cholerae (33). Given C. crescentus low nutrient habitat, it is surprising that PTS or ATP-binding cassette domain transporters, ...
A mutant variant of a septicemic Escherichia coli strain (L3) isolated from an outbreak in chickens was constructed by the insertion of TnphoA transposon. Seven mutant derivatives were analyzed regarding the pathogenicity. Two of them (XP2, XP4) were less pathogenic in the one-day-old chick pathogenicity assay. The expression of several outer membrane proteins of mutant XP2 strain was suppressed, and strain XP4 had a 47.8(kDa) protein that was not expressed. None of these proteins was correlated to the iron-acquisition system. Mutant XP2 could have suppression of a regulatory protein responsible for the expression of other proteins not related to pathogenicity but important for the rapid bacterial growth, while mutant XP4 did not express a 47.8(kDa) protein. We propose that the 47.8(kDa) protein could be associated to the pathogenicity process of Escherichia coli strains responsible for septicemia in poultry ...
The structural and functional differences between wild type (WT) outer membrane protein G and its two mutants are investigated with Fourier transform infrared spectroscopy. Both mutants have a long extension to the primary sequence to increase the number of beta-strands from 14 (wild type) to 16 in an attempt to enlarge the pore diameter. The comparison among proteins is made in terms of pH-dependent conformational changes and thermal stability. Results show that all proteins respond to pH change but at different degrees. At acidic environment, all proteins contain the same number of residues participated in beta-sheet structure. However, at neutral pH, the mutants have less ordered structure compared to WT porin. Thermal stability tests show that mutants differ significantly from WT porin at neutral pH. Although the transition temperature is directly proportional with the amount of beta-sheet content, the changes in the pre-transition phase that pave the way to structural breakdown are shown to ...
The membrane assembly of outer membrane proteins is more complex than that of transmembrane helical proteins owing to the intervention of many charged and polar residues in the membrane. Accordingly, the predictive accuracy of transmembrane beta strands is considerably lower than that of transmembrane alpha helices. In this paper we develop a set of conformational parameters for membrane spanning beta strands. We formulate an algorithm to predict the transmembrane beta strands in the family of bacterial porins based on the conformational parameters and surrounding hydrophobicities of amino acid residues. A Fortran program has been developed which takes the amino acid sequence as the input file and gives the predicted transmembrane beta strand as output. The present method predicts at an accuracy level of 82% for all the bacterial porins considered.
The susceptibility of the E. coli B strain to a variety of stressful conditions and antibiotics revealed by PM tests (Figure S3 in Additional file 1) can be explained by several observations (Figure 5). First, differences in the composition of the LPS core and expression of outer membrane proteins may influence the permeability and integrity of the cell envelope. B strains produce more OmpF porin than K-12 strains because the B genome lacks micF, which post-transcriptionally prevents production of OmpF [24]. This is further supported by the transcriptome data showing high levels of ompF expression in the B strain and high expression of ompC and ompA in the K-12 strain (Figure 4). These observations were also consistent with results of proteome analysis of the outer membrane fractions (Figure S2B in Additional file 1). Noxious agents such as antibiotics and bile acids diffuse more easily through OmpF than OmpC because the former produces a channel with a larger pore size [25]. Second, synthesis ...
Pseudomonas aeruginosa is an important cause of nosocomial infection and may lead to septicemia and death. P. aeruginosa septicaemia is associated with the highest mortality rate of all gram-negative infections. Because of the general resistance of the organism to antibiotics, research has been focused on immunotherapy. There are several bacterial cell components incorporated into subunit vaccines. Vaccine studies have often focussed on Lipo Poly Saccharide (LPS) and the outer membrane proteins (OPRs) due to its potent stimulation of the immune response. The pathophysiological nature of LPS and its serotype-specific immunological activities has limited LPS using for Pseudomona infection control whereas using major Outer Membrane Proteins of cell walls (mOMPs) of Pseudomonas aeruginosa and other gram-negative bacteria, not only is non-toxic and actively stimulate the immune system but also shows immunological cross-reactivity with mOMPs of other serotypes belonging to same species. Today, the ...
Protein TonB; Interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates. It could act to transduce energy from the cytoplasmic membrane to specific energy- requiring processes in the outer membrane, resulting in the release into the periplasm of ligands bound by these outer membrane proteins (249 aa ...
In the present study, antigenic cross-reactivity of OMPs was investigated in several species of bacterial pathogens. Heterogeneous mouse or fish antisera were used to ascertain OMPs with cross-reactivity and cluster analysis was performed to analyze the distribution of cross-antigenic OMPs in diverse bacterial strains. We interestingly found that eleven and seven bands could be reacted with four kinds of heterogeneous mouse and fish antisera, respectively, and the phenograms constructed could provide ideal targeted bacteria for candidate genes of polyvalent vaccines. Importantly, there were significant differences in reaction with bacteria between mouse and fish antisera, but commonly antigenic bands still existed between them. Our results suggest that the cross-reactivity of OMPs exists commonly in Gram-negative bacteria, which may be a promising choice for the development of polyvalent OMP vaccines. Meanwhile, cluster analysis will help to understand the relation of cross-antigenic OMPs among ...
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Motivation: Transmembrane beta-barrels exist in the outer membrane of gram-negative bacteria as well as in chloroplast and mitochondria. They are often involved in transport processes and are promising antimicrobial drug targets. Structures of only a few beta-barrel protein families are known. Therefore, a method that could automatically generate such models would be valuable. The symmetrical arrangement of the barrels suggests that an approach based on idealized geometries may be successful. Results: Here, we present tobmodel; a method for generating 3D models of beta-barrel transmembrane proteins. First, alternative topologies are obtained from the BOCTOPUS topology predictor. Thereafter, several 3D models are constructed by using different angles of the beta-sheets. Finally, the best model is selected based on agreement with a novel predictor, ZPRED3, which predicts the distance from the center of the membrane for each residue, i.e. the Z-coordinate. The Z-coordinate prediction has an average ...
Specific assembly proteins are required for the folding and integration of autotransporters into the outer membrane. Employing x-ray crystallography, the authors of the study decoded the atomic structure of the autotransporter assembly protein TamA of the intestinal bacterium Escherichia Coli.. The protein TamA, explains Fabian Gruss, first author and recipient of a Werner-Siemens PhD fellowship, also forms a barrel with a pore. The pore is closed to the outside by a lid but a particular kink in the barrel wall provides a gate for autotransporter substrates. When an unfolded autotransporter is delivered, TamA hooks onto one end of the substrate polypeptide chain and integrates it step by step via the gate into its own barrel structure. The TamA barrel is thus expanded; the pore widens and opens such that passenger substrates traverse to the exterior. The assembly process ends when TamA releases the autotransporter into the surrounding membrane. The autotransporter insertion mechanism was ...
1.B.55 The Poly Acetyl Glucosamine Porin (PgaA) Family. The linear homopolymer poly-beta-1,6-N-acetyl-D-glucosamine (beta-1,6-GlcNAc; PGA) serves as an adhesin for the maintenance of biofilm structural stability in diverse eubacteria. Its function in Escherichia coli K-12 requires the gene products of the pgaABCD operon, all of which are necessary for biofilm formation. PgaC is an apparent glycosyltransferase that is required for PGA synthesis, and PgaD is also needed for PGA formation. Deletion of genes for the predicted outer membrane proteins PgaA and PgaB did not prevent PGA synthesis but did block its export at the cell poles, the initial attachment site for biofilm formation (Itoh et al., 2008). PgaA contains a predicted beta-barrel porin and a superhelical domain containing tetratricopeptide repeats, which may mediate protein-protein interactions. It may form the outer membrane secretin for PGA. PgaB contains predicted carbohydrate binding and polysaccharide N-deacetylase domains. ...
The periplasm (the space between the inner and outer membranes of bacteria) is the site of activation of the periplasmic stress response. Like the cytosolic stress response and the eukaryotic endoplasmic and cytosolic stress responses, unfolded proteins trigger a transcriptional activation profile that allows cells to produce more chaperones and protein-folding agents (see Young and Hartl). Although, the periplasmic stress response is fairly well characterized, the sensor that initiates the process has remained elusive. The response consists of activation of the protease DegS, which cleaves transmembrane protein RseA, which then releases the transcription factor σE to allow the activation of stress response genes. Walsh et al. show that DegS is inhibited by its PDZ domain and that binding of the PDZ domain toYQF motifs of outer membrane protein porins activates the protease. Bacteria expressing DegS lacking the PDZ domain showed increased σE activity. Using an oriented peptide library, a ...
The outer membrane (OM) of Gram-negative pathogenic bacteria represents a platform for the secretion and presentation of surface-localized virulence factors. Th...
Abstract: The β-barrel assembly machinery (BAM) inserts outer membrane β-barrel proteins (OMPs) in the outer membrane of Gram-negative bacteria. In Enterobacteriacea, BAM also mediates export of the stress sensor lipoprotein RcsF to the cell surface by assembling RcsF-OMP complexes. Here, we report the crystal structure of the key BAM component BamA in complex with RcsF. BamA adopts an inward-open conformation, with the lateral gate to the membrane closed. RcsF is lodged deep within the lumen of the BamA barrel, binding regions proposed to undergo outward and lateral opening during OMP insertion. On the basis of our structural and biochemical data, we propose a push-and-pull model for RcsF export following conformational cycling of BamA, and provide a mechanistic explanation for how RcsF uses its interaction with BamA to detect envelope stress. Our data also suggest that the flux of incoming OMP substrates is involved in the control of BAM activity ...
CDS N E->G O3K_21210 sgrR transcriptional regulator SgrR E112/10 4518367 5211133 G->A CDS N A->T O3K_21840 inner membrane protein E112/10 4667748 5061192 G->A CDS N V->I O3K_22600 putative cell envelope opacity-associated protein E112/10 5176186 4552535 C->T CDS N R->H O3K_24910 rffA TDP-4-oxo-6-deoxy-D-glucose transaminase E112/10 174510 4279463.... YjiN / b4336 DUF445 domain-containing protein YjiN from Escherichia coli K-12 substr. MG1655 (see paper ...
1GFN: Structural and functional characterization of OmpF porin mutants selected for larger pore size. I. Crystallographic analysis.
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