Fig. 3. Dose–response curves of sikokianin C with the five mutant CBS proteins. (A) The activities of the wild-type and five mutant CBS proteins were determined by using the lead sulfide assay. (B–F) Dose–response curves of sikokianin C with the T193A CBS, N194A CBS, H203A CBS, Y223A CBS and Y308A CBS mutants. The mutation of each amino acid residue reduces the binding ability between CBS and sikokianin C to various degrees.
