Non-Covalent Interactions of Thymidylate Synthase and dCMP Hydroxymethylase

Speaker: Keith Z. Hazleton

Abstract:
Thymidylate Synthase (TS) and dCMP Hydroxymethylase (HM) are enzymes in
the dNTP synthetase complex of T4 infected e. coli. These two enzymes
participate in the synthesis of the two pyrimidine components of T4 DNA -
thymine and 5-hydroxymethylcytosine.

T4 DNA is At rich, with T being present at twice the level of C. The
activities of TS and HM match the consumption level of T and C, thus TS is
twice as active as HM in vivo. The in vitro reaction rates of the
isolated enzymes show that HM is the more active of the two enzyme. There
has been some work to show that HM and TS regulate each other's activities
in vivo to maintain the 2:1 reaction ratio.

Using purified HM and TS, kinetics experiments will be conducted to
measure the interactions of the two enzymes. Additionally, other enzymes
in the dNTP synthetase complex will be utilized to observe their effects
on the activity of TS and HM.