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Updated: Jul 5, 2026
12:07
Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues
Published on: November 22, 2014
Non-standard base pairing and stacked structures in methyl xanthine clusters
Michael P Callahan1, Zsolt Gengeliczki, Nathan Svadlenak
1Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA.
Physical Chemistry Chemical Physics : PCCP
|May 10, 2008
Summary
Methylated xanthine dimers exhibit distinct structures. 7-methylxanthine dimers show N3H hydrogen bonding, while theobromine and trimethylxanthine dimers form stacked structures, revealing insights into molecular interactions.
Area of Science:
- Physical Chemistry
- Molecular Spectroscopy
- Computational Chemistry
Background:
- Xanthine derivatives are important in biological systems.
- Understanding their aggregation and hydrogen bonding is crucial for pharmacology.
- Previous studies have explored monomeric forms, but dimeric structures require further investigation.
Purpose of the Study:
- To investigate the structures of methylated xanthine dimers using advanced spectroscopic techniques.
- To identify tautomeric forms of methylated xanthine monomers.
- To elucidate the nature of intermolecular interactions in methylated xanthine dimers.
Main Methods:
- Resonant two-photon ionization spectroscopy.
- Infrared-ultraviolet (IR-UV) double resonance spectroscopy.
- Laser desorption with supersonic jet expansion.
- Quantum chemical calculations of IR frequencies.
Main Results:
- Assigned the lowest energy tautomers for 7-methylxanthine, theophylline, and theobromine monomers.
- Identified three possible hydrogen bonding configurations (reverse Watson-Crick and two reverse Hoogsteen) for 7-methylxanthine dimer.
- Observed a stacked structure for theobromine dimer and inferred a stacked structure for trimethylxanthine dimers.
Conclusions:
- The study provides detailed structural information on methylated xanthine dimers.
- Spectroscopic and computational methods successfully differentiated tautomers and dimeric structures.
- Findings contribute to understanding molecular recognition and self-assembly in biologically relevant molecules.
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