Crystal structure of an intermolecular 2:1 complex between adenine and thymine. Evidence for both Hoogsteen and 'quasi-Watson-Crick' interactions

Sosale Chandrasekhar; Tangali R Ravikumar Naik; Susanta K Nayak; Tayur N Guru Row

doi:10.1016/j.bmcl.2010.04.131

Crystal structure of an intermolecular 2:1 complex between adenine and thymine. Evidence for both Hoogsteen and 'quasi-Watson-Crick' interactions

Bioorg Med Chem Lett. 2010 Jun 15;20(12):3530-3. doi: 10.1016/j.bmcl.2010.04.131. Epub 2010 May 20.

Authors

Sosale Chandrasekhar¹, Tangali R Ravikumar Naik, Susanta K Nayak, Tayur N Guru Row

Affiliation

¹ Department of Organic Chemistry, Indian Institute of Science, Bangalore, India. sosale@orgchem.iisc.ernet.in

PMID: 20493694
DOI: 10.1016/j.bmcl.2010.04.131

Abstract

The titled complex, obtained by co-crystallization (EtOH/25 degrees C), is apparently the only known complex of the free bases. Its crystal structure, as determined by X-ray diffraction at both 90 K and 313 K, showed that one A-T pair involves a Hoogsteen interaction, and the other a Watson-Crick interaction but only with respect to the adenine unit. The absence of a clear-cut Watson-Crick base pair raises intriguing questions about the basis of the DNA double helix.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenine / chemistry*
Base Pairing
Crystallography, X-Ray
DNA / chemistry
Temperature
Thymine / chemistry*

Substances

DNA
Adenine
Thymine