Crystallization and preliminary crystallographic analysis of BbCRASP-1, a complement regulator-acquiring surface protein of Borrelia burgdorferi

Borrelia burgdorferi is the causative agent of Lyme disease. Serum-resistant strains of the pathogen are able to reduce the host's immune response to infection by recruiting fluid-phase complement regulators from the serum. B. burgdorferi complement regulator-acquiring surface protein-1 (BbCRASP-1) binds factor H and factor-H-like protein-1 to the bacterial surface, where they actively down-regulate complement response. Crystals of native and selenomethionine-substituted BbCRASP-1 have been obtained and a native data set to 2.7 Angstrom as well as selenomethionine MAD data to 3.2 Angstrom resolution have been collected. The selenium substructure has been solved and initial phases have been refined to 3.0 Angstrom by density-modification methods. Model building and refinement are under way.