Download MendeleySuicide inactivation of the uracil DNA glycosylase UdgX by covalent complex formation.
Tu, J., Chen, R., Yang, Y., Cao, W., Xie, W.(2019) Nat Chem Biol 15: 615-622
- PubMed: 31101915
- DOI: https://doi.org/10.1038/s41589-019-0290-x
- Primary Citation of Related Structures:
6IO9, 6IOA, 6IOB, 6IOC, 6IOD - PubMed Abstract:
A uracil DNA glycosylase (UDG) from Mycobacterium smegmatis (MsmUdgX) shares sequence similarity with family 4 UDGs and forms exceedingly stable complexes with single-stranded uracil-containing DNAs (ssDNA-Us) that are resistant to denaturants. However, MsmUdgX has been reported to be inactive in excising uracil from ssDNA-Us and the underlying structural basis is unclear. Here, we report high-resolution crystal structures of MsmUdgX in the free, uracil- and DNA-bound forms, respectively. The structural information, supported by mutational and biochemical analyses, indicates that the conserved residue His109 located on a characteristic loop forms an irreversible covalent linkage with the deoxyribose at the apyrimidinic site of ssDNA-U, thus rendering the enzyme unable to regenerate. By proposing the catalytic pathway and molecular mechanism for MsmUdgX, our studies provide an insight into family 4 UDGs and UDGs in general.
Organizational Affiliation:
MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou, Guangdong, China.
