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Updated: May 29, 2026

In Vitro Chemical Mapping of G-Quadruplex DNA Structures by Bis-3-Chloropiperidines
Published on: May 12, 2023
Structure of 2,4-diaminopyrimidine-theobromine alternate base pairs
Zsolt Gengeliczki1, Michael P Callahan, Martin Kabeláč
1Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States.
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.
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