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Identification of six major outer membrane proteins from Actinobacillus actinomycetemcomitans
Hitoshi Komatsuzawa1, Ryuji Asakawa, Toshihisa Kawai
1Department of Microbiology, Hiroshima University Faculty of Dentistry, Kasumi 1-2-3, Minami-ku, Hiroshima City, Japan. hkomatsu@hiroshima-u.ac.jp
Abstract:
We have identified six major sarcosyl-insoluble outer membrane proteins (Omp) of Actinobacillus actinomycetemcomitans Y4, and designated them as Omp100, Omp64, Omp39, Omp29, Omp18 and Omp16 according to the molecular mass. A similar N-terminal sequence was found in the first 15 amino acid residues of Omp16 and Omp18. The N-terminal sequence of Omp29 matched perfectly with the sequence previously identified. We cloned and determined the DNA sequences of three complete genes encoding Omp100, Omp64 and Omp18/16, and one incomplete gene encoding Omp39. Each Omp revealed homologies with some bacterial virulence factors responsible for adhesion, invasion, serum resistance, or protein antigenicity. Serum from patients with periodontitis suspected to be related to A. actinomycetemcomintans infection strongly reacted with Omp100, Omp29 and Omp16 as did serum from mice immunized with A. actinomycetemcomitans Y4 whole bacteria. These findings suggest that Omps of A. actinomycetemcomitans can be associated with periodontal disease.
Insights
Six outer membrane proteins (Omps) from Actinobacillus actinomycetemcomitans were identified. These bacterial proteins may play a role in periodontal disease, as indicated by patient serum reactions.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Actinobacillus actinomycetemcomitans is implicated in periodontal disease.
- Outer membrane proteins (Omps) are key bacterial surface components.
Purpose of the Study:
- To identify and characterize outer membrane proteins (Omps) of Actinobacillus actinomycetemcomitans Y4.
- To investigate the potential role of these Omps in periodontal disease.
Main Methods:
- Protein identification and molecular mass determination.
- Gene cloning and DNA sequencing.
- N-terminal amino acid sequencing.
- Immune serum reactivity assays.
Main Results:
- Six major sarcosyl-insoluble Omps (Omp100, Omp64, Omp39, Omp29, Omp18, Omp16) were identified.
- Homologies suggest Omps possess virulence factor functions (adhesion, invasion, serum resistance).
- Patient and immunized mouse sera reacted strongly with Omp100, Omp29, and Omp16.
Conclusions:
- The identified Omps of Actinobacillus actinomycetemcomitans are potential virulence factors.
- These Omps are associated with the host immune response in periodontal disease.