Objective · To study the effect of sumoylation on the structure, stability and activity of human thymine DNA glycosylase (TDG).
Methods · Expression and purification systems were established for obtaining SUMO-1-TDG protein with high purity which can be used for crystal
screening and activity detection. Structure of SUMO-1-TDG was solved after crystal screening, diffraction data collection and structure analysis. The
change of TDG stability led by sumoylation was detected through a protein thermal shift assay. In addition, an activity assay was applied to investigate the
effect of sumoylation on the activity of TDG. Results · A high-resolution structure of SUMO-1-TDG which could clearly describe the interaction between
TDG and SUMO-1 was solved. The melting temperature (Tm) value of SUMO-1-TDG increased by about 16 ℃ and the catalytic activity increased by 9.70%,
comparing with TDG protein. Conclusion · SUMO-1 binds to TDG to modify the intermolecular interaction of amino acids near the binding site, and
further participates in the regulation of the stability and catalytic activity of TDG protein.