Effect of sumoylation on the structure and activity of human thymine DNA glycosylase / 上海交通大学学报（医学版）

ABSTRACT

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 ? 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.