XPF-like nuclease domain of Saccharomyces cerevisiae crossover junction endonuclease Mms4 and similar proteins
Budding yeast Mms4, also known as Eme1 in other organisms, is a putative transcriptional (co)activator that protects Saccharomyces cerevisiae cells from endogenous and environmental DNA damage. It interacts with MUS81 to form a DNA structure-specific endonuclease with substrate preference for branched DNA structures with a 5'-end at the branch nick. Typical substrates include 3'-flap structures, D-loops, replication forks with regressed leading strands and nicked Holliday junctions. The nuclease domain of Mms4 lacks the catalytic motif.
Comment:DNA-binding induced conformational changes in the linkers connecting the nuclease and nuclease-like domain of Mus81 and Eme1 facilitating the DNA substrate bending and ultimately place the incision strand at an active site of Mus81.
Comment:Based on the structure evidence that Homo sapiens Mus81-Eme1 complex binds flap DNA substrates