Vanoxonin, a new inhibitor of thymidylate synthetase, was found in cultured broths of the strain MG245-CF2 classified as Saccharopolyspora hirsuta. Vanoxonin, C18H25N3O9, was obtained as colorless powder. Vanoxonin forms a vanadium complex which exhibits a strong inhibition against thymidylate synthetase. The concentration for 50% inhibition of the enzyme (IC50) was 0.7 micrograms/ml.

The automatic identification of catalytic residues still remains an important challenge in structural bioinformatics. Sequence-based methods are good alternatives when the query shares a high percentage of identity with a well-annotated enzyme. However, when the homology is not apparent, which occurs with many structures from the structural genome initiative, structural information should be ex...

The ThyX class of thymidylate synthases was previously characterized by a common ThyX motif, RHRX7S. We report bacterial ThyX sequences having distinctive ThyX motifs, suggesting a more general ThyX motif, R/THRX7-8S. One ThyX sequence has an intein in its ThyX motif that was shown to do protein splicing and a group II intron in its gene, suggesting a hot spot for these self-splicing mobile ele...

The role of protein flexibility in enzyme-catalyzed activation of chemical bonds is an evolving perspective in enzymology. Here we examine the role of protein motions in the hydride transfer reaction catalyzed by thymidylate synthase (TSase). Being remote from the chemical reaction site, the Y209W mutation of Escherichia coli TSase significantly reduces the protein activity, despite the remar...

Exogenous thymine must be converted to thymidine to enable a thyA (thymidylate synthase) mutant to grow. The deoxyribose in the thymidine comes from dUMP, which must first be dephosphorylated. The nucleotidase YjjG is critical for this step. A yjjG thyA mutant cannot use thymine for growth on a glucose minimal medium.

A series of novel pyrrolo[2,3-d]pyrimidine derivatives was designed and synthesized as thymidylate synthase (TS) inhibitors. Molecular design was performed on the human TS complex model built on the basis of the reported structure of TS-deoxyuridinemonophosphate (dUMP)-CB3717 ternary complex. From a docking study, we expected that a one-carbon bridge between pyrrolo[2,3-d]pyrimidine and an arom...

The tritium atom of deoxyuridylate-5-3H is obligatorily displaced in the thymidylate synthetase reaction and equilibrates with water. Accordingly, a new and simple assay for the enzyme has been devised which is based on the measurement of the tritium released. This method shows essentially the same substrate requirements and pH optimum as the spectrophotometric assay. It has the advantage of mu...