Surface exposure and protease insensitivity of Borrelia burgdorferi Erp (OspEF-related) lipoproteins

Borrelia burgdorferi can encode numerous lipoproteins of the Erp family. Al though initially described as outer surface proteins, the technique used in that earlier study has since been demonstrated to disrupt bacterial membra nes and allow labelling of subsurface proteins. Data are now presented from additional analyses indicating that Erp proteins are indeed surface expose d in the outer membrane. Surface localization of these infection-associated proteins indicates the potential for interactions of Erp proteins with ver tebrate tissues, Some Erp proteins were resistant to in situ digestion by c ertain proteases, suggesting that those proteins fold in manners which hide protease cleavage sites, or that they interact with other protective membr ane components. Additionally, cultivation of B. burgdorferi in the presence of antibodies directed against Erp proteins inhibited bacterial growth.