Noncanonical substrate preference of lambda exonuclease for 5'-nonphosphate-ended dsDNA and a mismatch-induced acceleration effect on the enzymatic reaction.

ABSTRACT: Lambda exonuclease (λ exo) plays an important role in the resection of DNA ends for DNA repair. Currently, it is also a widely used enzymatic tool in genetic engineering, DNA-binding protein mapping, nanopore sequencing and biosensing. Herein, we disclose two noncanonical properties of this enzyme and suggest a previously undescribed hydrophobic interaction model between λ exo and DNA substrates. We demonstrate that the length of the free portion of the substrate strand in the dsDNA plays an essential role in the initiation of digestion reactions by λ exo. A dsDNA with a 5' non-phosphorylated, two-nucleotide-protruding end can be digested by λ exo with very high efficiency. Moreover, we show that when a conjugated structure is covalently attached to an internal base of the dsDNA, the prese

SUBMITTER: Wu T 

PROVIDER: S-EPMC5888420 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature