Purification and characterization of peritrichous fimbriae from Streptococcus oralis strain 2705

Abstract

We attempted to purify peritrichous fimbriae from Streptococcus oralis strain 2705. The fimbriae were purified by mechanical shearing, ammonium sulfate fractionation, and sucrose density gradient ultracentrifugation. Electron microscopy demonstrated the presence of dense masses of aggregated fimbriae. SDS-PAGE analysis revealed that the fimbriae consisted of a 16kDa protein. However, they were eluted at a void volume by Sepharose CL-6B gel filtration, suggesting the fimbriae are polymers of 16kDa monomer proteins. In colony immunoblotting, antiserum raised against the purified fimbriae reacted with strain 2705, but did not react with other peritrichous S. oralis or S. salivarius strains. This indicates that antigenically for different peritrichous fimbriae might exist in S. oralis.