| Autor: |
Juan C. Salazar, Arvind Anand, Star Dunham-Ems, Azad Eshghi, Caroline E. Cameron, Morgan LeDoyt, Amit Luthra, Daniel C. Desrosiers, Justin D. Radolf, Michael A. D. Cummings, Adriana R. Cruz, Melissa J. Caimano |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Molecular Microbiology. 80:1496-1515 |
| ISSN: |
0950-382X |
| DOI: |
10.1111/j.1365-2958.2011.07662.x |
| Popis: |
Definitive identification of Treponema pallidum rare outer membrane proteins (OMPs) has long eluded researchers. TP0326, the sole protein in T. pallidum with sequence homology to a Gram-negative OMP, belongs to the BamA family of proteins essential for OM biogenesis. Structural modelling predicted that five polypeptide transport-associated (POTRA) domains comprise the N-terminus of TP0326, while the C-terminus forms an 18-stranded amphipathic β-barrel. Circular dichroism, heat modifiability by SDS-PAGE, Triton X-114 phase partitioning and liposome incorporation supported these topological predictions and confirmed that the β-barrel is responsible for the native protein's amphiphilicity. Expression analyses revealed that native TP0326 is expressed at low abundance, while a protease-surface accessibility assay confirmed surface exposure. Size-exclusion chromatography and blue native polyacrylamide gel electrophoresis revealed a modular Bam complex in T. pallidum larger than that of Escherichia coli. Non-orthologous ancillary factors and self-association of TP0326 via its β-barrel may both contribute to the Bam complex. T. pallidum-infected rabbits mount a vigorous antibody response to both POTRA and β-barrel portions of TP0326, whereas humans with secondary syphilis respond predominantly to POTRA. The syphilis spirochaete appears to have devised a stratagem for harnessing the Bam pathway while satisfying its need to limit surface antigenicity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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