Sequence analysis and recombinant expression of a 28-kilodalton Treponema pallidum subsp. pallidum rare outer membrane protein (Tromp2).

ABSTRACT Immune evasion and disease progression of Treponema pallidum subsp. pallidum are associated with sequence diversity in the hypervariable outer membrane protein TprK. Previous attempts to study variation within TprK have sequenced at depths insufficient to fully appreciate the hypervariable nature of the protein, failed to establish linkage between the protein’s seven variable regions, or were conducted on isolates passed through rabbits. As a consequence, a complete profile of tprK during infection in the human host is still lacking. Furthermore, prior studies examining how T. pallidum subsp. pallidum uses its repertoire of genomic donor sites to generate diversity within the variable regions of the tprK have yielded a partial understanding of this process due to the limited number of tprK alleles examined. In this study, we used short- and long-read deep sequencing to directly characterize full-length tprK alleles from T. pallidum subsp. pallidum collected from early lesions of patients attending two sexually transmitted infection clinics in Italy. We demonstrate that strains collected from cases of secondary syphilis contain significantly more unique variable region sequences and full-length TprK sequences than those from cases of primary syphilis. Our data, combined with recent data available on Chinese T. pallidum subsp. pallidum specimens, show the near-complete absence of overlap in TprK sequences among the 41 specimens profiled to date. We further estimate that the potential antigenic variability carried by TprK rivals that of current estimates of the human adaptive immune system. These data underscore the immunoevasive ability of TprK that allows T. pallidum subsp. pallidum to establish lifelong infection. IMPORTANCE Syphilis continues to be a significant public health issue in both low- and high-income countries, including the United States where the rate of syphilis infection has increased over the past 5 years. Treponema pallidum subsp. pallidum, the causative agent of syphilis, carries the outer membrane protein TprK that undergoes segmental gene conversion to constantly create new sequences. We performed full-length deep sequencing of TprK to examine TprK diversity in clinical T. pallidum subsp. pallidum strains. We then combined our results with data from all samples for which TprK deep sequencing results were available. We found almost no overlap in TprK sequences between different patients. Moreover, our data allowed us to estimate the total number of TprK variants that T. pallidum subsp. pallidum can potentially generate. Our results support how the T. pallidum subsp. pallidum TprK antigenic variation system is an equal adversary of the human immune system leading to pathogen persistence in the host.

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Molecular cloning and sequence analysis of a developmentally regulated cysteine-rich outer membrane protein from Chlamydia trachomatis

Gene ◽

10.1016/0378-1119(88)90047-9 ◽

1988 ◽

Vol 71 (2) ◽

pp. 307-314 ◽

Cited By ~ 29

Author(s):

Ian N. Clarke ◽

Michael E. Ward ◽

Paul R. Lambden

Keyword(s):

Sequence Analysis ◽

Chlamydia Trachomatis ◽

Membrane Protein ◽

Outer Membrane ◽

Molecular Cloning ◽

Outer Membrane Protein ◽

Developmentally Regulated

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Point mutations in the major outer membrane protein drive hypervirulence of a rapidly expanding clone of Campylobacter jejuni

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1605869113 ◽

2016 ◽

Vol 113 (38) ◽

pp. 10690-10695 ◽

Cited By ~ 35

Author(s):

Zuowei Wu ◽

Balamurugan Periaswamy ◽

Orhan Sahin ◽

Michael Yaeger ◽

Paul Plummer ◽

...

Keyword(s):

Sequence Analysis ◽

Membrane Protein ◽

Outer Membrane ◽

Campylobacter Jejuni ◽

Outer Membrane Protein ◽

Animal Health ◽

Major Outer Membrane Protein ◽

Whole Genome Sequence ◽

Bacterial Strains ◽

Zoonotic Pathogen

Infections due to clonal expansion of highly virulent bacterial strains are clear and present threats to human and animal health. Association of genetic changes with disease is now a routine, but identification of causative mutations that enable disease remains difficult. Campylobacter jejuni is an important zoonotic pathogen transmitted to humans mainly via the foodborne route. C. jejuni typically colonizes the gut, but a hypervirulent and rapidly expanding clone of C. jejuni recently emerged, which is able to translocate across the intestinal tract, causing systemic infection and abortion in pregnant animals. The genetic basis responsible for this hypervirulence is unknown. Here, we developed a strategy, termed “directed genome evolution,” by using hybridization between abortifacient and nonabortifacient strains followed by selection in an animal disease model and whole-genome sequence analysis. This strategy successfully identified SNPs in porA, encoding the major outer membrane protein, are responsible for the hypervirulence. Defined mutagenesis verified that these mutations were both necessary and sufficient for causing abortion. Furthermore, sequence analysis identified porA as the gene with the top genome-wide signal of adaptive evolution using Fu’s Fs, a population genetic metric for recent population size changes, which is consistent with the recent expansion of clone “sheep abortion.” These results identify a key virulence factor in Campylobacter and a potential target for the control of this zoonotic pathogen. Furthermore, this study provides general, unbiased experimental and computational approaches that are broadly applicable for efficient elucidation of disease-causing mutations in bacterial pathogens.

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A preliminary study on the proinflammatory mechanisms of Treponema pallidum outer membrane protein Tp92 in human macrophages and HMEC-1 cells

Microbial Pathogenesis ◽

10.1016/j.micpath.2017.06.046 ◽

2017 ◽

Vol 110 ◽

pp. 176-183 ◽

Cited By ~ 6

Author(s):

Xi Luo ◽

Xiaohong Zhang ◽

Tie Zhao ◽

Tiebing Zeng ◽

Wen Liu ◽

...

Keyword(s):

Membrane Protein ◽

Outer Membrane ◽

Outer Membrane Protein ◽

Treponema Pallidum ◽

Human Macrophages ◽

Preliminary Study

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TP0453, a Concealed Outer Membrane Protein of Treponema pallidum, Enhances Membrane Permeability

Journal of Bacteriology ◽

10.1128/jb.187.18.6499-6508.2005 ◽

2005 ◽

Vol 187 (18) ◽

pp. 6499-6508 ◽

Cited By ~ 25

Author(s):

Karsten R. O. Hazlett ◽

David L. Cox ◽

Marc Decaffmeyer ◽

Michael P. Bennett ◽

Daniel C. Desrosiers ◽

...

Keyword(s):

Membrane Protein ◽

Outer Membrane ◽

Outer Membrane Protein ◽

Outer Membrane Proteins ◽

Nutrient Transport ◽

Treponema Pallidum ◽

Protein S ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Membrane Spanning

ABSTRACT The outer membrane of Treponema pallidum, the noncultivable agent of venereal syphilis, contains a paucity of protein(s) which has yet to be definitively identified. In contrast, the outer membranes of gram-negative bacteria contain abundant immunogenic membrane-spanning β-barrel proteins mainly involved in nutrient transport. The absence of orthologs of gram-negative porins and outer membrane nutrient-specific transporters in the T. pallidum genome predicts that nutrient transport across the outer membrane must differ fundamentally in T. pallidum and gram-negative bacteria. Here we describe a T. pallidum outer membrane protein (TP0453) that, in contrast to all integral outer membrane proteins of known structure, lacks extensive β-sheet structure and does not traverse the outer membrane to become surface exposed. TP0453 is a lipoprotein with an amphiphilic polypeptide containing multiple membrane-inserting, amphipathic α-helices. Insertion of the recombinant, nonlipidated protein into artificial membranes results in bilayer destabilization and enhanced permeability. Our findings lead us to hypothesize that TP0453 is a novel type of bacterial outer membrane protein which may render the T. pallidum outer membrane permeable to nutrients while remaining inaccessible to antibody.

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