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N-terminal domain of the actinomycetal Nei1 and related DNA glycosylases This family contains the N-terminal domain of the actinomycetal Nei1 and related DNA glycosylases. It belongs to the FpgNei_N, [N-terminal domain of Fpg (formamidopyrimidine-DNA glycosylase, MutM)_Nei (endonuclease VIII)] domain superfamily. DNA glycosylases maintain genome integrity by recognizing base lesions created by ionizing radiation, alkylating or oxidizing agents, and endogenous reactive oxygen species. They initiate the base-excision repair process, which is completed with the help of enzymes such as phosphodiesterases, AP endonucleases, DNA polymerases and DNA ligases. DNA glycosylases cleave the N-glycosyl bond between the sugar and the damaged base, creating an AP (apurinic/apyrimidinic) site. Most FpgNei DNA glycosylases use their N-terminal proline residue as the key catalytic nucleophile, and the reaction proceeds via a Schiff base intermediate. This family contains mostly actinomycetes and includes Mycobacterium tuberculosis Nei1 (MtuNei1). MtuNei1 recognizes oxidized pyrimidines such as thymine glycol (Tg) and 5,6-dihydrouracil on both double stranded and single stranded DNA, it has a strong preference for the 5R isomer of Tg. In addition to this domain, enzymes belonging to this family contain a helix-two turn-helix (H2TH) domain and a zinc-finger motif. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",