Mechanistic studies of different thymidylate synthases and the role of protein dynamics in catalysis (110.1)

Abstract

Thymidylate synthases (TSases) catalyze the last committed step in the de novo biosynthesis of thymidylate, one of the four DNA bases (T). Classical TSases catalyze a complex cascade, and we developed methods to study the physical nature of its mechanism, and to test the role of enzyme dynamics in catalysis. In a related study, a newly discovered family of TSases was examined. We used a combination of isotopic labeling, mutations, quench-flow, and X-ray crystallography (Fig. 1), and found an unusual chemical mechanism for these flavin-dependent thymidylate synthases (FDTS). Figure 1. An active site view of crystal structures of TmFDTS in complex with FAD, dUMP, and the co-factor CH2H4folate.