Structure of 2,4-diaminopyrimidine-theobromine alternate base pairs.

Authors :: Gengeliczki Z
Callahan MP
Kabeláč M
Rijs AM
de Vries MS
Source :: The journal of physical chemistry. A [J Phys Chem A] 2011 Oct 20; Vol. 115 (41), pp. 11423-7. Date of Electronic Publication: 2011 Sep 02.
Publication Year :: 2011
Abstract: We report the structure of clusters of 2,4-diaminopyrimidine with 3,7-dimethylxanthine (theobromine) in the gas phase determined by IR-UV double resonance spectroscopy in both the near-IR and mid-IR regions in combination with ab initio computations. These clusters represent potential alternate nucleobase pairs, geometrically equivalent to guanine-cytosine. We have found the four lowest energy structures, which include the Watson-Crick base pairing motif. This Watson-Crick structure has not been observed by resonant two-photon ionization (R2PI) in the gas phase for the canonical DNA base pairs.