Toward a detailed understanding of base excision repair enzymes: transition state and mechanistic analyses of N-glycoside hydrolysis and N-glycoside transfer

Base excision repair (BER) are enzymes that remove nucleobases from DNA in the first step of DNA damage repair. The review illustrates the contributions that transition state (TS) analysis has made to understanding BER enzymes. Most TS analysis have involved N-glycoside hydrolyses and N-glycosyl transfers with nucleosides. These studies combined with other mechanistic studies make it possible to elucidate the chemistry of deoxynucleosides and BER enzymes including superfamilies, uracil DNA glycosylases (UDG) and HhH superfamily. Finally, it is emphasized that TS analysis is very important particularly for enzymes where the basic details of catalysis remain open questions.