Bacterial Thymidylate Synthase Binds Two Molecules of Substrate and Cofactor without Cooperativity.

ABSTRACT: Thymidylate synthase (TSase) is a clinically important enzyme because it catalyzes synthesis of the sole de novo source of deoxy-thymidylate. Without this enzyme, cells die a "thymineless death" since they are starved of a crucial DNA synthesis precursor. As a drug target, TSase is well studied in terms of its structure and reaction mechanism. An interesting mechanistic feature of dimeric TSase is that it is "half-the-sites reactive", which is a form of negative cooperativity. Yet, the basis for this is not well-understood. Some experiments point to cooperativity at the binding steps of the reaction cycle as being responsible for the phenomenon, but the literature contains conflicting reports. Here we use ITC and NMR to resolve these inconsistencies. This first detailed thermodynamic disse

SUBMITTER: Sapienza PJ 

PROVIDER: S-EPMC4699426 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature