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Molecular cloning and characterization of the genes encoding the immunoreactive major cell-surface proteins of
1Department of Oral Microbiology, Osaka University Faculty of Dentistry, Suita-Osaka, Japan.
Abstract:
A 72-kDa major cell-surface protein (72K-CSP) was purified from the wash fluid of Porphyromonas gingivalis OMZ409. Using the synthetic oligonucleotide probes corresponding to the determined amino-terminal amino acid sequence of 72K-CSP, recombinant plasmid clones carrying approx. 3.4-kb KpnI-XhoI fragments in XL1-Blue libraries of P. gingivalis OMZ409 and 381 were obtained. The premature form proteins of 558 and 563 amino acids led by putative signal sequences were thought to be processed to form the mature proteins of a predicted size of 55,655 Da for strain OMZ409 and of 55,654 for strain 381. Both proteins had unusual proline-rich regions in their carboxyl-terminal regions. No homologous sequences could be found in protein databases. Examination of antigen-specific antibody responses in the serum of patients with adult periodontitis by ELISA revealed that 72K-CSP had a different immunoreactivity from that of P. gingivalis 381 fimbriae.
Insights
Researchers purified a 72-kDa cell-surface protein (72K-CSP) from Porphyromonas gingivalis. This protein, distinct from fimbriae, showed unique immunoreactivity in adult periodontitis patients.
Area of Science:
- Microbiology
- Immunology
- Proteomics
Background:
- Porphyromonas gingivalis is a key pathogen in adult periodontitis.
- Cell-surface proteins play crucial roles in bacterial adhesion and host interaction.
- Understanding P. gingivalis surface proteins can reveal novel diagnostic or therapeutic targets.
Purpose of the Study:
- To purify and characterize a major cell-surface protein (72K-CSP) from P. gingivalis OMZ409.
- To investigate the genetic basis and protein structure of 72K-CSP.
- To assess the immunological relevance of 72K-CSP in adult periodontitis.
Main Methods:
- Purification of 72K-CSP from P. gingivalis wash fluid.
- Oligonucleotide probe-based screening of recombinant plasmid libraries (P. gingivalis OMZ409 and 381).
- ELISA to examine antigen-specific antibody responses in patient serum.
Main Results:
- A 72-kDa cell-surface protein (72K-CSP) was successfully purified.
- Recombinant clones encoding 72K-CSP precursors (558/563 amino acids) were obtained from P. gingivalis strains OMZ409 and 381.
- The mature proteins were predicted to be ~55 kDa, featuring proline-rich carboxyl-terminal regions with no database homology.
- ELISA showed 72K-CSP has distinct immunoreactivity compared to P. gingivalis 381 fimbriae in periodontitis patients.
Conclusions:
- 72K-CSP is a novel, proline-rich cell-surface protein of P. gingivalis.
- The genetic and structural analysis provides insights into its processing and characteristics.
- 72K-CSP exhibits unique immunological properties, differentiating it from known P. gingivalis virulence factors like fimbriae, suggesting its potential role in periodontitis pathogenesis.