[摘要]：Exonuclease X is a 3'-5' distributive exonuclease that functions in DNA recombination and repair It undergoes multiple rounds of binding, hydrolysis, and release to degrade long substrate molecules and thus is very inefficient. In order to identify a cofactor that elevates the excision activity of ExoX, we screened many proteins involved in repair and recombination We observed that MutL greatly promoted the exonuclease activity of ExoX, and then verified the interaction between MutL and ExoX using SPR and Far-Western analysis This promotion is independent of ATP and the DNA-binding activity of Mutt. We constructed two deletion mutants to analyze this interaction and its regulation of ExoX activity, and found that this functional interaction with ExoX is mainly due to ionic interactions with the N-terminus of MutL This adds a new role to Mutt. and gives a clue to MutL's possible regulation on other DnaQ family exonuclease members (C) 2010 Elsevier Inc. All rights reserved
