5′-Methylthioadenosine (MTA) and S-adenosylhomocysteine (SAH) are important metabolites in all living organisms. Two similar nucleosidases for hydrolyzing MTA in Arabidopsis thaliana (AtMTAN1 and AtMTAN2) exist, but only AtMTAN2 shows markedly broad substrate specificity for hydrolysis of SAH. To examine the biochemical characteristics of AtMTAN2, it was over-expressed in Escherichia coli and purified to homogeneity. Spectroscopic assays confirm AtMTAN2 catalyzes MTA as well as SAH hydrolysis, compared to AtMTAN1 which only hydrolyzes MTA. In addition, crystal structure of the AtMTAN2 enzyme in complex with, adenine was determined at 2.9 Å resolution. Finally, a structural comparison of AtMTAN2 performed with previously determined structures of AtMTAN1 and an E. coli homolog provides clues for the substrate specificity of MTA nucleosidases in A. thaliana.
|Number of pages
|Biochemical and biophysical research communications
|Published - 2009 Apr 17
Bibliographical noteFunding Information:
We thank the staff at 4A beamline, Pohang Light Source, Korea and NW12 beamline, Photon Factory, Japan for helping with the data collection. This work was supported by grants from the Plant Signaling Network Research Center and Molecular and Cellular Biodiscovery Research Program (M10648230002-08N4823-00210), Korea Science and Engineering Foundation.
- Crystal structure
- Flexible loop
- Spectroscopic assay
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology