We provide a detailed analysis of the glycosylase activity and binding affinity of five MUTYH variants.
A variant in the FCL motif of MUTYH (P281L) has minimal glycosylase activity due to an inability to bind to substrate DNA.
R295C and R520Q MUTYH have low levels of active enzyme, exhibit compromised affinity for damaged DNA and reduced base excision catalysis.
Q324H and P502L have nearly WT glycosylase activity, but exhibit reduced affinity for protein partners Hus1 (of the 9#3−3#1 complex) and PCNA, respectively.
R520Q MUTYH also exhibits compromised affinity for PCNA suggesting a dual role for Arg 520 in OG:A mismatch recognition and interaction with PCNA.