Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
J Biol Chem. 2006 Aug 18;281(33):24048-57. Epub 2006 May 17.

Catalytic mechanism and structure of viral flavin-dependent thymidylate synthase ThyX.

Author information

  • 1CNRS, UMR 7645, Laboratory of Optics and Biosciences, Ecole Polytechnique, 91128 Palaiseau, France.

Abstract

By using biochemical and structural analyses, we have investigated the catalytic mechanism of the recently discovered flavin-dependent thymidylate synthase ThyX from Paramecium bursaria chlorella virus-1 (PBCV-1). Site-directed mutagenesis experiments have identified several residues implicated in either NADPH oxidation or deprotonation activity of PBCV-1 ThyX. Chemical modification by diethyl pyrocarbonate and mass spectroscopic analyses identified a histidine residue (His53) crucial for NADPH oxidation and located in the vicinity of the redox active N-5 atom of the FAD ring system. Moreover, we observed that the conformation of active site key residues of PBCV-1 ThyX differs from earlier reported ThyX structures, suggesting structural changes during catalysis. Steady-state kinetic analyses support a reaction mechanism where ThyX catalysis proceeds via formation of distinct ternary complexes without formation of a methyl enzyme intermediate.

PMID:
16707489
[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk