Mechanism of "S.millerli" to adhere with internal organs : a laminin-mediated process

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09672112
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 矯正・小児・社会系歯学
• Research Institution: Kagoshima University
• Principal Investigator: KITADA Katsuhiro Kagoshima Univ.Dental Sch., Research Associate, 歯学部, 助手 (90195264)
• Co-Investigator(Kenkyū-buntansha): ITO Hiro-O Kagoshima Univ.Dental Sch., Associate Professor, 歯学部, 助教授 (40213079) ; SATO Setsuko Kagoshima Univ.Dental Hosp., Assistant Professor, 歯学部・附属病院, 講師 (70145514)
• Project Period (FY): 1997 – 1998
• Keywords: Streptococcus milleri / laminin / enolase / extracellular matrix / tissue adhesion / gene cloning / polymerase chain reaction (PCR)

Research Abstract

The purpose of this study was to elucidate the mechanism of adherence of "Streptococcus milleri" group bacteria to host tissues. S.anginosus, S.consteratus and S.intermedius, the 3 "S.milleri" group species, were analyzed for their abilities to attach to several extracellular matrix (ECM) proteins. S.intermedius strains possessed a characteristic high laminin-binding ability. A proteinaceous substance with the laminin-binding ability was isolated from water-soluble cell surface substances of S.inlermedius ATCC 27335^T. The sequence of N-terminal 11 amino acids was determined and found to show a high level of homology with enolase of Staphylococcus aureus an enzyme involved in the glycolytic pathway. It has been recently suggested that the enzyme is involved in the tissue attachment of group A streptococci through its plasminogen-binding capacity. Then, we decided to clone the gene of S.intermedius enolase to assess the ECM-binding properties of the protein. Probes for the polymerase chain reaction (PCR) were synthesized, on the basis of the reported sequence of S.aureus enolase, and the gene encoding S.intermedius enolase was cloned. The deduced amino acid sequence of the S.intermedius enolase was about 80% homologous to that of S.aureus. Thus, the present study first determined the primary structure of S.intermedius enolase gene. The recombinant protein product of cloned enolase gene was expressed, and its laminin-binding property was confirmed. Enolase, an intracellular enzyme, may be translocated to the cell surface of S.intermedius by an unknown mechanism, and play an important role in establishment of infection through the laminin-binding capacity.