Isolation of an outer membrane protein complex from Borrelia burgdorferi by n-butanol extraction and high-performance ion-exchange chromatography

Borrelia burgdorferi, the causative agent of Lyme disease, expresses two major membrane proteins, designated outer surface proteins A and B, which are of antigenic relevance, especially in the chronic phase of Lyme disease. Both proteins exhibit strain-related molecular weight variation. A method is described for obtaining these proteins from the bacterial membrane, without the use of detergents, by a combination of n-butanol extraction and cation-exchange chromatography on a Mono S fast protein liquid chromatographic column. This method yields up to five times larger amounts of the proteins in aqueous solution than previously described protocols, which applied ionic or non-ionic detergents. A comparison of extracts obtained by this method from different Borrelia burgdorferi strains is reported.