Enzymatic excision of uracil residues in nucleosomes depends on the local DNA structure and dynamics.

ABSTRACT: The excision of uracil bases from DNA is accomplished by the enzyme uracil DNA glycosylase (UNG). Recognition of uracil bases in free DNA is facilitated by uracil base pair dynamics, but it is not known whether this same mechanistic feature is relevant for detection and excision of uracil residues embedded in nucleosomes. Here we investigate this question using nucleosome core particles (NCPs) generated from Xenopus laevis histones and the high-affinity "Widom 601" positioning sequence. The reactivity of uracil residues in NCPs under steady-state multiple-turnover conditions was generally decreased compared to that of free 601 DNA, mostly because of anticipated steric effects of histones. However, some sites in NCPs had equal or even greater reactivity than free DNA, and the observed react

SUBMITTER: Ye Y 

PROVIDER: S-EPMC3448002 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature