Structural studies of MutM and abasic site interstrand crosslink

B. Landova, A. Huskova, E. Boura, J. Silhan

Department of Biochemistry and Molecular Biology, Institute of Organic chemistry and Biochemistry, Flemingovo namesti , Prague

Bacterial MutM is a DNA repair glycosylase removing DNA damage generated form oxidative stress and preventing mutations and genomic instability. MutM belongs to the Fpg/Nei family of procaryotic enzymes sharing structural and functional similarities with their eukaryotic counterparts, for example, NEIL1-NEIL3. We present two crystal structure of MutM from pathogenic Neisseria meningitidis, MutM holoenzyme and MutM bound to DNA. The free enzyme exists in an open conformation, while upon binding to DNA, both the enzyme and DNA undergo substantial structural changes and domain rearrangement1.

One of DNA lesion repairing by MutM is abasic site (Ap site) which if not repaired may spontaneously lead to creation of abasic interstrand crosslink (Ap-ICL) with an adjacent adenine in the opposite strand. NEIL3 glycosylase is known to remove Ap-ICL. With an array of different oligonucleotides, we have investigate the rates of formation, the yields, and the stability of Ap-ICL. Our findings point out how different bases in the vicinity of the AP site change crosslink formation in vitro2.

1. Landova, B., and Silhan, J. (2020) Conformational changes of DNA repair glycosylase MutM triggered by DNA binding, Febs Letters 594, 3032-3044.

2. Huskova, A., Landova, B., Boura, E., Silhan, J. (2022) The rate of formation and stability of abasic site interstrand crosslink in the DNA duplex, DNA repair 103300.