CRASP-2 is encoded by the spirochete B. burgdorferi, which is carried by Ixodes ticks. Strain B31 is the type strain (ATCC 35210) for this organism and was derived by limited dilutional cloning from the original Lyme-disease tick isolate obtained by A. Barbour (Johnson, et al., 1984). B. burgdorferi differ in their susceptibility to normal human serum and are therefore classified as complement-resistant, complement-sensitive and intermediate complement-sensitive. Complement resistant bacteria absorb human immune regulators FHL-1/reconectin and factor H using two outer surface Complement Regulator-Acquiring Surface Proteins (CRASP-1 and CRASP-2). Surface-attached FHL-1/reconectin retains its complement regulatory and cleavage activity (Kraiczy, et al., 2001). Factor H and FHL-1 serve as cofactors for factor I, a serine protease that cleaves complement component 3b (C3b) directly on the cell surface and thereby ensures resistance of spirochetes to complement-mediated lysis (Kraiczya, et al., 2007). CRASP-2 (CSPz) is a 20kD/21kD protein which binds to FHL-1 and factor H binding protein (although it interacts preferentially with Factor H) and may be predominantly expressed by serum-resistant Borrelia strains (Rossmann, et al., 2006). It is possible that because of discontinuous binding regions in the factor H/FHL-1, a long-distance interaction may be involved in binding of both immune regulators. Putative coiled-coil structural elements may also be important in the interaction of B. burgdorferi CRASP-1 with factor H (Kraiczya, et al., 2007). These proteins represent another immune evasion mechanism of B. burgdorferi, as bacteria acquire human complement regulators to control complement activation on their surface and prevent formation of toxic activation products (Kraiczy, et al., 2001).
Recombinant protein corresponding to Borrelia burgdorferi CRASP-2, strain B31, fused to an MBP-Tag, expressed in E. coli.
Molecular Weight:~67.8kD (25.4kD for CRASP-2 and 42.4kD for MBP)
Storage and Stability:Aliquot to avoid repeated freezing and thawing and store at -70°C. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：100ug
Source Antigen：Recombinant, E. coli
Grade：Purified
Purity：~90% (SDS-PAGE)
Form：Supplied as a liquid in PBS, pH 7.2, 0.01% sodium azide.
