Repair of 8-oxoG:A mismatches by the MUTYH glycosylase: Mechanism, metals and medicine

- MutY is a unique BER glycosylase that removes adenine from 8-oxoG:A mispairs.
- Dysfunctional MUTYH variants are associated with MUTYH-associated polyposis (MAP).
- There are many MAP variants that have a myriad of functional consequences.
- MUTYH contains a recently identified Zinc-linchpin motif that is required for efficient mismatch recognition and repair.
- New structural and mechanistic information indicated that MutY is a retaining glycosidase.

Reactive oxygen and nitrogen species (RONS) may infringe on the passing of pristine genetic information by inducing DNA inter- and intra-strand crosslinks, protein-DNA crosslinks, and chemical alterations to the sugar or base moieties of DNA. 8-Oxo-7,8-dihydroguanine (8-oxoG) is one of the most prevalent DNA lesions formed by RONS and is repaired through the base excision repair (BER) pathway involving the DNA repair glycosylases OGG1 and MUTYH in eukaryotes. MUTYH removes adenine (A) from 8-oxoG:A mispairs, thus mitigating the potential of G:C to T:A transversion mutations from occurring in the genome. The paramount role of MUTYH in guarding the genome is well established in the etiology of a colorectal cancer predisposition syndrome involving variants of MUTYH, referred to as MUTYH-associated polyposis (MAP). In this review, we highlight recent advances in understanding how MUTYH structure and related function participate in the manifestation of human disease such as MAP. Here we focus on the importance of MUTYH's metal cofactor sites, including a recently discovered “Zinc linchpin” motif, as well as updates to the catalytic mechanism. Finally, we touch on the insight gleaned from studies with MAP-associated MUTYH variants and recent advances in understanding the multifaceted roles of MUTYH in the cell, both in the prevention of mutagenesis and tumorigenesis.

199