DNA repair enzyme that has both DNA N-glycosylase activity and AP-lyase activity. Initiates repair at cis-syn pyrimidine dimers. Proceeds via an imino enzyme:DNA intermediate. Binds 1 [4Fe-4S] cluster. Readthrough of the terminator UAG occurs between codons for Gly-268 and Ala-270. Two forms of 31 kDa and 32 kDa have been detected. Belongs to the Nth/MutY family.