MUTAGENESIS OF OUTER-MEMBRANE VIRULENCE DETERMINANTS OF THE ORAL SPIROCHETE TREPONEMA-DENTICOLA

The pore-forming major surface protein (Msp) and the chymotrypsin-like protease (CTLP) of Treponema denticola ATCC 35405 have been implicate d in periodontal pathogenicity. Allelic replacement mutations were con structed at two sites in the msp gene and at one site in the CTLP locu s. All mutant strains lacked the Msp hexagonal array outer membrane ul trastructure, strain CKE, in which the locus encoding CTLP was disrupt ed, produced no CTLP and had aberrant Msp expression. The msp mutant M HE lacked Msp, and produced increased levels of CTLP, In contrast, msp mutant MPE made small amounts of a truncated Msp, but produced no CTL P. Interactions between Msp and CTLP in transport or assembly of the o uter membrane complex are proposed, (C) 1998 Federation of European Mi crobiological Societies. Published by Elsevier Science B.V. All rights reserved.