Format

Send to

Choose Destination
See comment in PubMed Commons below
Acta Crystallogr D Biol Crystallogr. 2011 Sep;67(Pt 9):784-91. doi: 10.1107/S0907444911024814. Epub 2011 Aug 9.

Structure of trifunctional THI20 from yeast.

Author information

1
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA.

Abstract

In a recently characterized thiamin-salvage pathway, thiamin-degradation products are hydrolyzed by thiaminase II, yielding 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP). This compound is an intermediate in thiamin biosynthesis that, once phosphorylated by an HMP kinase, can be used to synthesize thiamin monophosphate. Here, the crystal structure of Saccharomyces cerevisiae THI20, a trifunctional enzyme containing an N-terminal HMP kinase/HMP-P kinase (ThiD-like) domain and a C-terminal thiaminase II (TenA-like) domain, is presented. Comparison to structures of the monofunctional enzymes reveals that while the ThiD-like dimer observed in THI20 resembles other ThiD structures, the TenA-like domain, which is tetrameric in all previously reported structures, forms a dimer. Similarly, the active site of the ThiD-like domain of THI20 is highly similar to other known ThiD enzymes, while the TenA-like active site shows unique features compared with previously structurally characterized TenAs. In addition, a survey of known TenA structures revealed two structural classes, both of which have distinct conserved features. The TenA domain of THI20 possesses some features of both classes, consistent with its ability to hydrolyze both thiamin and the thiamin-degradation product 2-methyl-4-amino-5-aminomethylpyrimidine.

PMID:
21904031
PMCID:
PMC3169313
DOI:
10.1107/S0907444911024814
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for International Union of Crystallography Icon for PubMed Central
    Loading ...
    Support Center