Cosolute paramagnetic relaxation enhancements detect transient conformations of human uracil DNA glycosylase (hUNG).

ABSTRACT: The human DNA repair enzyme uracil DNA glycosylase (hUNG) locates and excises rare uracil bases that arise in DNA from cytosine deamination or through dUTP incorporation by DNA polymerases. Previous NMR studies of hUNG have revealed millisecond time scale dynamic transitions in the enzyme-nonspecific DNA complex, but not the free enzyme, that were ascribed to a reversible clamping motion of the enzyme as it scans along short regions of duplex DNA in its search for uracil. Here we further probe the properties of the nonspecific DNA binding surface of {(2)H(12)C}{(15)N}-labeled hUNG using a neutral chelate of a paramagnetic Gd(3+) cosolute (Gd(HP-DO3A)). Overall, the measured paramagnetic relaxation enhancements (PREs) on R(2) of the backbone amide protons for free hUNG and its DNA complex w

SUBMITTER: Sun Y 

PROVIDER: S-EPMC3232301 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature