This family consists of the major outer sneath proteins of Treponema lecithinolyticum and Treponema maltophilum. These proteins are localized in the outer membrane and form heat-modifiable, detergent and trypsin-stable complexes, suggesting a ß-barrel structure. However, they have not shown any channel activity and no sequence similarity to the MspA of Treponema denticola, therefore are chosen to comprise a different family.