Involved in base excision repair of DNA damaged by oxidation or by mutagenic agents. DNA glycosylase that recognizes and removes damaged pyrimidines. Excises Tg:A (thymine glycol, prefers 5R isomers), Tg:G, 5,6-dihydrouracil:G base pairs and urea:A, also excises oxidized purine derivatives guanidinohydantoin:C and spiroiminodihydantoin:C. Poorly cleaves dsDNA with uracil substitutions, thus also acting as a weak uracil-DNA glycosylase. Acts on DNA bubble and 3'-fork structures, suggesting a role in replication-associated DNA repair. Activity on 7,8-dihydro-8-oxoguanine (8-oxoG) is debated; a report shows weak activity (PubMed:18457574), whereas another shows none (PubMed:20031487). Has AP (apurinic/apyrimidinic) activity and introduces nicks in dsDNA strand, inefficiently cleaves ssDNA with AP sites and uracil. Probably cleaves the DNA backbone by beta-delta elimination to generate a single-strand break at the site of the removed base with both 3'- and 5'-phosphates. Cleaves ssDNA containing an AP site. Complements an E.coli fpg mutY but not nei nth double mutant (PubMed:18457574). 2'-deoxyribonucleotide-(2'-deoxyribose 5'-phosphate)-2'-deoxyribonucleotide-DNA = a 3'-end 2'-deoxyribonucleotide-(2,3-dehydro-2,3-deoxyribose 5'-phosphate)-DNA + a 5'-end 5'-monophospho-2'-deoxyribonucleoside-DNA + H(+) Binds 1 zinc ion per subunit. Expressed in mid-log phase. Belongs to the FPG family. There are 2 paralogs in M.tuberculosis, in some references this gene is called nei2 (PubMed:18457574 and PubMed:19496823).