Areas of Interest
DNA damage is an unavoidable challenge of cellular life. The base excision repair (BER) pathway, present in all domains of life, is tasked with removing diverse single-base DNA lesions and incorporating new nucleotides to properly complement the opposing strand. Glycosylase family enzymes catalyze the first step of BER, wherein a lesion is detected and the damaged base is cleaved at the N-glycosidic bond to create an abasic site. This is typically accomplished through a base-flipping mechanism which rotates the target base out of the DNA helix and into the enzyme active site for cleavage. The human alkyladenine DNA glycosylase (AAG) acts by such a mechanism, and it excises a broad range of substrates including common methyl and ethenopurine adducts. Despite the enzyme’s known role excising lesions such as 1,N6-ethenoadenine, N3-methyladenine, N7-methylguanine, and hypoxanthine, its full substrate range remains unclear. Likewise, the structural features of the enzyme’s active site which allow it to identify and excise such a wide spectrum of lesions have yet to be characterized. My project focuses on using transient and steady state enzyme kinetics to learn more about the substrate specificity of AAG.