MglA and mglB of Treponema denticola; similarity to ABC transport and spa genes.

The mglA and mglB genes (td-mglA and td-mglB) of the oral spirochete Treponema denticola were sequenced. These two T. denticola genes are highly homologous to the E. coli and Treponema pallidum mglA and mglB genes which are part of the three gene beta-methylgalactoside transport operon, mglBAC. Both Td-mglA and td-mglB are also homologous to the high affinity ABC-type transporters for ribose and arabinose, and surface presentation antigens (spa) locus, part of the type III secretion systems in enteropathogens. Td-mglB and td-mglA are co-transcribed as a single mRNA in T. denticola as well as in E. coli cells as determined by reverse transcription PCR (RT-PCR). Homology to td-mglB and its expressed protein was found in other oral spirochetes as determined by Southern and western blot analysis.