Self-resistance mechanism for secondary metabolite-accumulating species-Structure and function of okadaic acid-binding proteins

冈田酸结合蛋白OABP_s 2. 1和2. 3的重组蛋白在E.杆菌重组OABP_s中OA的解离常数2. 1和2. 3在结合试验中测定。冈田酸结合蛋白可能是海绵蛋白，而不是共生物种的海绵蛋白。此外，我们定量了冈田酸和OABP2。1在从日本各地收集的海绵中，推测了一种可能是自卫系统的海绵。

Okadaic acid binding proteins OABP_s 2. 1 and 2. 3, originally isolated from the sponge Halichondria okadai, were stably expressed as recombinant proteins in E. coli. Dissociation constants of OA from recombinant OABP_s 2. 1 and 2. 3 were determined in the binding assays. The okadaic acid binding proteins were deduced to be the sponge proteins but not those from symbiotic species. Furthermore, we quantitated okadaic acid and OABP2. 1 in the sponge collected from various places in Japan, and speculated a possible self-defense system of the sponge.