scholarly journals Outer Membrane Secretion Efficiency of Autotransporter Virulence Proteins Correlates with Passenger Domain Folding Properties

2011 ◽  
Vol 100 (3) ◽  
pp. 516a ◽  
Author(s):  
Jonathan P. Renn ◽  
Mirco Junker ◽  
Patricia L. Clark
Keyword(s):  
Outer Membrane ◽  
Passenger Domain ◽  
Virulence Proteins ◽  
Secretion Efficiency

scholarly journals Importance of Conserved Residues of the Serine Protease Autotransporter β-Domain in Passenger Domain Processing and β-Barrel Assembly

2010 ◽  
Vol 78 (8) ◽  
pp. 3516-3528 ◽  
Author(s):  
Yihfen T. Yen ◽  
Casey Tsang ◽  
Todd A. Cameron ◽  
Dennis O. Ankrah ◽  
Athina Rodou ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Serine Protease ◽  
Cell Fractionation ◽  
Passenger Domain ◽  
Double Mutation ◽  
Conserved Residues ◽  
Virulence Proteins ◽  
Secretion Pathway ◽  
Residue Substitution ◽  
Cellular Compartments

ABSTRACT Serine protease autotransporters of the family Enterobacteriaceae (SPATE) comprise a family of virulence proteins secreted by enteric Gram-negative bacteria via the autotransporter secretion pathway. A SPATE polypeptide contains a C-terminal translocator domain that inserts into the bacterial outer membrane as a β-barrel structure and mediates secretion of the passenger domain to the extracellular environment. In the present study, we examined the role of conserved residues located in the SPATE β-barrel-forming region in passenger domain secretion. Thirty-nine fully conserved residues in Tsh were mutated by single-residue substitution, and defects in their secretion phenotypes were assessed by cell fractionation and immunochemistry. A total of 22 single mutants exhibited abnormal phenotypes in different cellular compartments. Most mutants affecting secretion are charged residues with side chains pointing into the β-barrel interior. Seven mutants showed notable abnormalities in processing (constructs with the E1231A, E1249A, and R1374A mutations) and β-barrel assembly or insertion into the outer membrane (constructs with the G1158Y, F1360A, Y1375A, and F1377A mutations). The phenotypes of the β-barrel assembly/insertion mutants and the presence of a processed Tsh passenger domain in the periplasm support the possibility that the translocator domain must undergo extensive folding prior to insertion into the outer membrane. Results from double-mutation experiments further demonstrate that F1360 and F1377 affect β-barrel insertion/assembly at different times. In light of these new data, a more refined model for the mechanism of SPATE secretion is presented.

scholarly journals The Role of Virulence Proteins in Protection Conferred by Bordetella pertussis Outer Membrane Vesicle Vaccines

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 429
Author(s):  
René H. M. Raeven ◽  
Naomi van Vlies ◽  
Merijn L. M. Salverda ◽  
Larissa van der Maas ◽  
Joost P. Uittenbogaard ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Bordetella Pertussis ◽  
Protective Immunity ◽  
Membrane Vesicle ◽  
Outer Membrane Proteins ◽  
Outer Membrane Vesicle ◽  
Protective Capacity ◽  
T Helper 1 ◽  
Virulence Proteins ◽  
Humoral Responses

The limited protective immunity induced by acellular pertussis vaccines demands development of novel vaccines that induce broader and longer-lived immunity. In this study, we investigated the protective capacity of outer membrane vesicle pertussis vaccines (omvPV) with different antigenic composition in mice to gain insight into which antigens contribute to protection. We showed that total depletion of virulence factors (bvg(-) mode) in omvPV led to diminished protection despite the presence of high antibody levels. Antibody profiling revealed overlap in humoral responses induced by vaccines in bvg(-) and bvg(+) mode, but the potentially protective responses in the bvg(+) vaccine were mainly directed against virulence-associated outer membrane proteins (virOMPs) such as BrkA and Vag8. However, deletion of either BrkA or Vag8 in our outer membrane vesicle vaccines did not affect the level of protection. In addition, the vaccine-induced immunity profile, which encompasses broad antibody and mixed T-helper 1, 2 and 17 responses, was not changed. We conclude that the presence of multiple virOMPs in omvPV is crucial for protection against Bordetella pertussis. This protective immunity does not depend on individual proteins, as their absence or low abundance can be compensated for by other virOMPs.

scholarly journals Antigenic Organization of the N-Terminal Part of the Polymorphic Outer Membrane Proteins 90, 91A, and 91B of Chlamydophilaabortus

2003 ◽  
Vol 71 (6) ◽  
pp. 3240-3250 ◽  
Author(s):  
Evangelia Vretou ◽  
Panagiota Giannikopoulou ◽  
David Longbottom ◽  
Evgenia Psarrou
Keyword(s):  
Outer Membrane ◽  
Binding Sites ◽  
Outer Membrane Proteins ◽  
Single Amino Acid ◽  
Antigenic Peptides ◽  
Terminal Part ◽  
Passenger Domain ◽  
Recombinant Peptides ◽  
Type V ◽  
Reference Strains

ABSTRACT A series of overlapping recombinant antigens, 61 to 74 residues in length, representing polymorphic outer membrane protein 90 (POMP90) of Chlamydophila abortus and two recombinant peptides spanning gene fragment p91Bf99 of POMP91B were assessed by immunoblotting to determine the antigen-binding sites of 20 monoclonal antibodies to POMP90, -91A, and -91B. The epitopes were further restricted by scanning 52 overlapping synthetic 12-mer peptides representing the N-terminal part of POMP90, and the 12-mer epitopes were then analyzed by using hexapeptides to the resolution of a single amino acid. Ten epitopes were defined: 1, TSEEFQVKETSSGT; 2, SGAIYTCEGNVCISYAGKDSPL; 3, SLVFHKNCSTAE; 4, AIYADKLTIVSGGPTLFS; 5, SPKGGAISIKDS; 6, ITFDGNKIIKTS; 7, LRAKDGFGIFFY; 7a, DGFGIF; 7b, GIFFYD; 8, IFFYDPITGGGS; 8a, FFYDPIT; 9, GKIVFSGE; and 10, DLGTTL. The 20-mer peptide LRAKDGFGIFFYDPITGGGS was a major epitope that was recognized by seven antibodies. Epitopes 7 to 10 were conserved in reference strains of the former species C. psittaci, whereas the strong antigenic peptides FYDPIT and IVFSGE were conserved among members of the genus Chlamydophila. Epitopes 3 to 8 were located within the best-scoring beta-helical wrap (residues 148 to 293) predicted for POMP91B by the program BETAWRAP. Other studies have suggested an association of the POMPs with type V secretory autotransporter proteins. The results presented in this study provide some evidence for a passenger domain that is folded as a beta-helix pyramid with compact antigenic organization.

scholarly journals Sequential Translocation of Polypeptides across the Bacterial Outer Membrane through the Trimeric Autotransporter Pathway

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Rakesh Sikdar ◽  
Harris D. Bernstein
Keyword(s):  
Outer Membrane ◽  
Alternative Energy ◽  
Protein Translocation ◽  
Outer Membrane Proteins ◽  
Passenger Domain ◽  
Experimental Conditions ◽  
Content Type ◽  
Intrinsically Disordered ◽  
Extracellular Domains ◽  
Bacterial Outer Membrane

ABSTRACT Trimeric autotransporter adhesins (TAAs) are a family of bacterial outer membrane (OM) proteins that are comprised of three identical subunits. Each subunit contains an N-terminal extracellular (“passenger”) domain and a short C-terminal segment that contributes four β strands to a single 12-stranded β barrel. The mechanism by which the passenger domains are translocated across the OM and the energetics of the translocation reaction are poorly understood. To address these issues, we examined the secretion of modified versions of the passenger domain of UpaG, a TAA produced by Escherichia coli CFT073. Using the SpyTag-SpyCatcher system to probe passenger domain localization, we found that both intrinsically disordered polypeptides fused to the UpaG passenger domain and artificially disulfide-bonded polypeptides were secreted effectively but relatively slowly. Surprisingly, we also found that in some cases, the three nonnative passenger domain segments associated with a single trimer were secreted sequentially. Photo-cross-linking experiments indicated that incompletely assembled UpaG derivatives remained bound to the barrel assembly machinery (Bam) complex until all three passenger domains were fully secreted. Taken together, our results strongly suggest that the secretion of polypeptides through the TAA pathway is coordinated with the assembly of the β barrel domain and that the folding of passenger domains in the extracellular space maximizes the rate of secretion. Furthermore, our work provides evidence for an unprecedented sequential mode of protein translocation, at least under specific experimental conditions. IMPORTANCE Trimeric autotransporter adhesins (TAAs) are specialized bacterial outer membrane proteins consisting of three identical subunits. TAAs contain large extracellular domains that trimerize and promote virulence, but the mechanism by which they are secreted is poorly understood. We found that the extracellular domains of a native TAA were secreted rapidly but that disordered and artificially folded polypeptides fused to native passenger domains were secreted in a slow, sequential fashion. Our results strongly suggest that the efficient secretion of native extracellular domains is driven by their trimerization following export but that alternative energy sources can be harnessed to secrete nonnative polypeptides. Furthermore, we obtained evidence that TAA extracellular domains are secreted before the assembly of the linked membrane spanning domain is completed.

scholarly journals Molecular Analysis of Transport and Oligomerization of the Yersinia enterocolitica Adhesin YadA

2003 ◽  
Vol 185 (13) ◽  
pp. 3735-3744 ◽  
Author(s):  
Andreas Roggenkamp ◽  
Nikolaus Ackermann ◽  
Christoph A. Jacobi ◽  
Konrad Truelzsch ◽  
Harald Hoffmann ◽  
...  
Keyword(s):  
Head And Neck ◽  
Outer Membrane ◽  
Infection Model ◽  
Passenger Domain ◽  
Adhesion Properties ◽  
Mouse Infection Model ◽  
C Terminus ◽  
Bacterial Adhesins ◽  
Significant Attenuation ◽  
Functional Features

ABSTRACT The Yersinia adhesin YadA is the prototype of a novel class of bacterial adhesins which form oligomeric lollipop-like structures and are anchored in the outer membrane by the C terminus. For YadA, six different regions (R) or domains (D) are predicted from the amino acid sequence: the N-terminal leader sequence, head-D, neck-D, stalk-D, linking-R, and a C-terminal transmembrane region consisting of four β-strands. To identify structural and functional features of these domains, we performed in-frame deletion mutagenesis and constructed N-terminally tagged YadA variants. Diverse YadA variants were analyzed for outer membrane localization, surface exposure, oligomerization adhesion properties, and ability to protect against complement-mediated lysis. We demonstrated that (i) the C-terminal region (amino acids [aa] 353 to 422) is sufficient for outer membrane insertion and formation of trimers in the outer membrane; (ii) the head, neck, and stalk domains (aa 26 to 330) are surface exposed, forming a passenger domain; and (iii) the linking region (aa 331 to 369) is responsible for outer membrane translocation of the passenger domain. Thus, YadA meets all the criteria of an autotransporter. The same may be true for all other members of the YadA family, forming a subfamily of surface-attached oligomeric autotransporters. Moreover, in-frame truncation mutagenesis suggested that the head and neck domains together form the YadA-binding module which is located on the top of the stalk. However, the YadA-binding module did not confer serum resistance. Mutants lacking the head and neck domain were resistant to complement-mediated lysis. In-frame truncation of the stalk domain did not result in significant attenuation of the mutant in an orogastric mouse infection model.

scholarly journals Characterization of an Immunogenic Outer Membrane Autotransporter Protein, Arp, of Bartonella henselae

2007 ◽  
Vol 75 (11) ◽  
pp. 5255-5263 ◽  
Author(s):  
Christine M. Litwin ◽  
Mindy L. Rawlins ◽  
Erica M. Swenson
Keyword(s):  
Amino Acid ◽  
Molecular Mass ◽  
Outer Membrane ◽  
Dna Sequences ◽  
Bartonella Henselae ◽  
Cross Reactivity ◽  
Passenger Domain ◽  
Calculated Molecular Mass ◽  
Reading Frame

ABSTRACT Bartonella henselae is a recently recognized pathogenic bacterium associated with cat scratch disease, bacillary angiomatosis, and bacillary peliosis. This study describes the cloning, sequencing, and characterization of an antigenic autotransporter gene from B. henselae. A cloned 6.0-kb BclI-EcoRI DNA fragment expresses a 120-kDa B. henselae protein immunoreactive with 21.2% of sera from patients positive for B. henselae immunoglobulin G antibodies by indirect immunofluorescence, with 97.3% specificity and no cross-reactivity with antibodies against various other organisms. DNA sequencing of the clone revealed one open reading frame of 4,320 bp with a deduced amino acid sequence that shows homology to the family of autotransporters. The autotransporters are a group of proteins that mediate their own export through the outer membrane and consist of a passenger region, the α-domain, and an outer membrane transporter region, the β-domain. The passenger domain shows homology to a family of pertactin-like adhesion proteins and contains seven, nearly identical 48-amino-acid repeats not found in any other bacterial or Bartonella DNA sequences. The passenger α-domain has a calculated molecular mass of 117 kDa, and the transporter β-domain has a calculated molecular mass of 36 kDa. The clone expresses a 120-kDa protein and a protein that migrates at approximately 38 kDa exclusively in the outer membrane protein fraction, suggesting that the 120-kDa passenger protein remains associated with the outer membrane after cleavage from the 36-kDa transporter.

The Bam (Omp85) complex is involved in secretion of the autotransporter haemoglobin protease

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3982-3991 ◽  
Author(s):  
Ana Sauri ◽  
Zora Soprova ◽  
David Wickström ◽  
Jan-Willem de Gier ◽  
Roel C. Van der Schors ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Critical Role ◽  
Structural Data ◽  
Intermediate Stage ◽  
Gram Negative Bacteria ◽  
Passenger Domain ◽  
Gram Negative ◽  
Periplasmic Chaperone ◽  
Folded Structures

Autotransporters are large virulence factors secreted by Gram-negative bacteria. They are synthesized with a C-terminal domain that forms a β-barrel pore in the outer membrane implicated in translocation of the upstream ‘passenger’ domain across the outer membrane. However, recent structural data suggest that the diameter of the β-barrel pore is not sufficient to allow the passage of partly folded structures observed for several autotransporters. Here, we have used a stalled translocation intermediate of the autotransporter Hbp to identify components involved in insertion and translocation of the protein across the outer membrane. At this intermediate stage the β-domain was not inserted and folded as an integral β-barrel in the outer membrane whereas part of the passenger was surface exposed. The intermediate was copurified with the periplasmic chaperone SurA and subunits of the Bam (Omp85) complex that catalyse the insertion and assembly of outer-membrane proteins. The data suggest a critical role for this general machinery in the translocation of autotransporters across the outer membrane.

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