10.1021/acsnano.6b00393.s001
Chi Zhang
Chi
Zhang
Lei Xie
Lei
Xie
Yuanqi Ding
Yuanqi
Ding
Qiang Sun
Qiang
Sun
Wei Xu
Wei
Xu
Real-Space
Evidence of Rare Guanine Tautomer Induced
by Water
American Chemical Society
2016
noncanonical DNA base tautomers
Rare Guanine Tautomer Induced
base tautomers
scanning tunneling microscopy imaging
formation
DNA base tautomers
2016-02-13 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Real_Space_Evidence_of_Rare_Guanine_Tautomer_Induced_by_Water/2245819
Water
is vital for life as a solvent. Specifically, it has been
well established that DNA molecules are hydrated in vivo, and water
has been found to be responsible for the presence of some noncanonical
DNA base tautomers. Theoretical investigations have shown that the
existence of water could significantly influence the relative stability
of different DNA base tautomers, reduce the energy barrier of tautomeric
conversions, and thus promote the formation of some rare base tautomers.
In this work, we report the real-space experimental evidence of rare
base tautomers. From the high-resolution scanning tunneling microscopy
imaging, we surprisingly find the formation of the rare guanine tautomer, <i>i.e.</i>, G/(3H,7H) form, on the Au(111) surface by delicately
introducing water into the system. The key to the formation of this
rare tautomer is proposed to be the “water bridge” that
largely reduces the energy barriers of intramolecular proton-transfer
processes as revealed by extensive density functional theory calculations.
The real-space experimental evidence and the proposed mechanism make
a step forward toward the fundamental understanding of water-assisted
base tautomerization processes.