scholarly journals A Supercomplex Spanning the Inner and Outer Membranes Mediates the Biogenesis of β-Barrel Outer Membrane Proteins in Bacteria

2016 ◽  
Vol 291 (32) ◽  
pp. 16720-16729 ◽  
Author(s):  
Yan Wang ◽  
Rui Wang ◽  
Feng Jin ◽  
Yang Liu ◽  
Jiayu Yu ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Outer Membranes

Analysis of the Membrane proteins of an Antarctic Bacterium Pseudomonas Syringae

2011 ◽  
Vol 4 ◽  
pp. PRI.S5383 ◽  
Author(s):  
M.V. Jagannadham ◽  
S. Saranya
Keyword(s):  
Comparative Analysis ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Pseudomonas Syringae ◽  
Cold Adaptation ◽  
Outer Membrane Proteins ◽  
Protein Preparation ◽  
Preparation Methods ◽  
Outer Membranes ◽  
Antarctic Bacterium

The proteins of an Antarctic bacterium Pseudomonas syringae Lz4W, identified earlier by different membrane protein preparation methods, were combined together and the redundant identities removed. In total, 1479 proteins including 148 outer membrane proteins from this bacterium were predicted by the algorithm PSORTb3.0. A detailed analysis on their subcellular localization was undertaken which was determined using TMHMM, TMB-hunt and BOMP. A comparison of PSORTb predicted outer membrane proteins with BOMP, revealed that most of the proteins predicted by the former, contained β–barrels in the outer membranes. A comparative analysis of PSORTb, TMHMM and TMB-hunt reveals that most of the outer membranes proteins of this bacterium could be identified using this approach. Thus, by using a combination of biochemical and different bioinformatics algorithms, the membrane proteins of P. syringae are analyzed. In particular, PSORTb results are compared and supported by other algorithms, to improve the strength of OM proteins prediction. Several proteins, having an important role in cold adaptation of the organism, could also be identified.

scholarly journals Omp85Tt from Thermus thermophilus HB27: an Ancestral Type of the Omp85 Protein Family

2008 ◽  
Vol 190 (13) ◽  
pp. 4568-4575 ◽  
Author(s):  
Jutta Nesper ◽  
Alexander Brosig ◽  
Philippe Ringler ◽  
Geetika J. Patel ◽  
Shirley A. Müller ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Single Channel ◽  
Cell Envelope ◽  
Thermus Thermophilus ◽  
Outer Membrane Proteins ◽  
Thermophilic Bacterium ◽  
Outer Membranes ◽  
Β Sheet ◽  
Ancestral Type

ABSTRACT Proteins belonging to the Omp85 family are involved in the assembly of β-barrel outer membrane proteins or in the translocation of proteins across the outer membrane in bacteria, mitochondria, and chloroplasts. The cell envelope of the thermophilic bacterium Thermus thermophilus HB27 is multilayered, including an outer membrane that is not well characterized. Neither the precise lipid composition nor much about integral membrane proteins is known. The genome of HB27 encodes one Omp85-like protein, Omp85Tt, representing an ancestral type of this family. We overexpressed Omp85Tt in T. thermophilus and purified it from the native outer membranes. In the presence of detergent, purified Omp85Tt existed mainly as a monomer, composed of two stable protease-resistant modules. Circular dichroism spectroscopy indicated predominantly β-sheet secondary structure. Electron microscopy of negatively stained lipid-embedded Omp85Tt revealed ring-like structures with a central cavity of ∼1.5 nm in diameter. Single-channel conductance recordings indicated that Omp85Tt forms ion channels with two different conducting states, characterized by conductances of ∼0.4 nS and ∼0.65 nS, respectively.

scholarly journals A Topology Structure Based Outer Membrane Proteins Segment Alignment Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Han Wang ◽  
Bo Liu ◽  
Pingping Sun ◽  
Zhiqiang Ma
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Transmembrane Proteins ◽  
Structure Alignment ◽  
Spatial Structures ◽  
Alignment Method ◽  
Outer Membranes ◽  
Novel Method ◽  
Segment Orientation

Outer membrane proteins (OMPs) are transmembrane proteins (TMPs) located in outer membranes. These proteins perform diverse biochemical functions and have immediate medical relevance, so that their spatial structures are important for studying. But the special physicochemical properties of OMP make it hard to obtain their structures experimentally. For the purpose of predicting OMP structures, discriminating OMPs and aligning their sequences to native structures are indispensable steps. We developed a novel method OMSA (Outer Membrane Segment Alignment), which implemented both steps in one program. OMSA integrates OMP-specific topology features to implement a sequence-to-structure alignment, for example, segment type and segment orientation, while a segment-dependent gap penalty model is employed to improve the alignment. Compared to peer top-leading methods, OMSA achieved higher accuracy in both OMP discrimination and alignment, which may further improve OMP structure studying.

scholarly journals Immunogenicity of Mannheimia haemolytica Recombinant Outer Membrane Proteins Serotype 1-Specific Antigen, OmpA, OmpP2, and OmpD15

2011 ◽  
Vol 18 (12) ◽  
pp. 2067-2074 ◽  
Author(s):  
Sahlu Ayalew ◽  
Binu Shrestha ◽  
Marie Montelongo ◽  
Amanda E. Wilson ◽  
Anthony W. Confer
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Recombinant Proteins ◽  
Outer Membrane Proteins ◽  
Specific Antigen ◽  
Antibody Responses ◽  
Mannheimia Haemolytica ◽  
Content Type ◽  
Outer Membranes ◽  
Serotype 1

ABSTRACTWe previously identifiedMannheimia haemolyticaouter membrane proteins (OMPs) that may be important immunogens by using immunoproteomic analyses. Genes for serotype 1-specific antigen (SSA-1), OmpA, OmpP2, and OmpD15 were cloned and expressed, and recombinant proteins were purified. Objective 1 of this study was to demonstrate immunogenicity of the four recombinant OMPs in mice and cattle. Objective 2 was to determine if the addition of individual recombinant OMPs or combinations of them would modify immune responsiveness of mice to the recombinant chimeric protein SAC89, containing the main epitope fromM. haemolyticaouter membrane lipoprotein PlpE and the neutralizing epitope ofM. haemolyticaleukotoxin. Mice vaccinated with recombinant OmpA (rOmpA), rSSA-1, rOmpD15, and rOmpP2 developed significant antibody responses toM. haemolyticaouter membranes and to the homologous recombinant OMP. Cattle vaccinated with rOmpA and rSSA-1 developed significant antibodies toM. haemolyticaouter membranes by day 28, whereas cattle vaccinated with rOmpD15 and rOmpP2 developed only minimal responses. Sera from cattle vaccinated with each of the recombinant proteins stimulated complement-mediated killing of the bacterium. Concurrent vaccination with SAC89 plus any of the four rOMPs singly resulted in increased endpoint anti-SAC89 titers, and for the SAC89/rSSA-1 vaccinees, the response was increased significantly. In contrast, the SAC89/P2/SSA-1 and SAC89/OmpA/P2/D15/SSA-1 combination vaccines resulted in significant decreases in anti-SAC89 antibodies compared to SAC89 vaccination alone. In conclusion, under the conditions of these experiments, vaccination of mice and cattle with rOmpA and rSSA-1 stimulated high antibody responses and may have protective vaccine potential.

scholarly journals The Conservation of Low Complexity Regions in Bacterial Proteins Depends on the Pathogenicity of the Strain and Subcellular Location of the Protein

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 451
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Subcellular Location ◽  
Low Complexity ◽  
Extracellular Proteins ◽  
Bacterial Strains ◽  
Bacterial Proteins ◽  
Protein Subcellular Location

Low complexity regions (LCRs) in proteins are characterized by amino acid frequencies that differ from the average. These regions evolve faster and tend to be less conserved between homologs than globular domains. They are not common in bacteria, as compared to their prevalence in eukaryotes. Studying their conservation could help provide hypotheses about their function. To obtain the appropriate evolutionary focus for this rapidly evolving feature, here we study the conservation of LCRs in bacterial strains and compare their high variability to the closeness of the strains. For this, we selected 20 taxonomically diverse bacterial species and obtained the completely sequenced proteomes of two strains per species. We calculated all orthologous pairs for each of the 20 strain pairs. Per orthologous pair, we computed the conservation of two types of LCRs: compositionally biased regions (CBRs) and homorepeats (polyX). Our results show that, in bacteria, Q-rich CBRs are the most conserved, while A-rich CBRs and polyA are the most variable. LCRs have generally higher conservation when comparing pathogenic strains. However, this result depends on protein subcellular location: LCRs accumulate in extracellular and outer membrane proteins, with conservation increased in the extracellular proteins of pathogens, and decreased for polyX in the outer membrane proteins of pathogens. We conclude that these dependencies support the functional importance of LCRs in host–pathogen interactions.

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