Summary information and primary citation
- PDB-id
-
5dbb;
DSSR-derived features in text and
JSON formats
- Class
- transferase-DNA
- Method
- X-ray (2.25 Å)
- Summary
- Structure of human DNA polymerase beta host-guest
complex with the dg base paired with a da
- Reference
-
Kou Y, Koag MC, Lee S (2015): "N7
Methylation Alters Hydrogen-Bonding Patterns of Guanine
in Duplex DNA." J.Am.Chem.Soc.,
137, 14067-14070. doi: 10.1021/jacs.5b10172.
- Abstract
- N7-Alkyl-2'-deoxyguanosines are major adducts in DNA
that are generated by various alkylating mutagens and
drugs. However, the effect of the N7 alkylation on the
hydrogen-bonding patterns of the guanine remains poorly
understood. We prepared N7-methyl-2'-deoxyguanosine
(N7mdG)-containing DNA using a transition-state
destabilization strategy, developed a novel polβ-host-guest
complex system, and determined eight crystal structures of
N7mdG or dG paired with dC, dT, dG, and dA. The structures
of N7mdG:dC and N7mdG:dG are very similar to those of dG:dC
and dG:dG, respectively, indicating the involvement of the
keto tautomeric form of N7mdG in the base pairings with dC
and dG. On the other hand, the structure of N7mdG:dT shows
that the mispair forms three hydrogen bonds and adopts a
Watson-Crick-like geometry rather than a wobble geometry,
suggesting that the enol tautomeric form of N7mdG involves
in its base pairing with dT. In addition, N7mdG:dA adopts a
novel shifted anti:syn base pair presumably via the enol
tautomeric form of N7mdG. The polβ-host-guest complex
structures reveal that guanine-N7 methylation changes the
hydrogen-bonding patterns of the guanine when paired with
dT or dA and suggest that N7 alkylation may alter the base
pairing patterns of guanine by promoting the formation of
the rare enol tautomeric form of guanine.
