Crystallographic studies on damaged DNAs: III. N(4)-methoxycytosine can form both Watson-Crick type and wobbled base pairs in a B-form duplex
Hossain, M.T., Chatake, T., Hikima, T., Tsunoda, M., Sunami, T., Ueno, Y., Matsuda, A., Takenaka, A.(2001) J Biochem 130: 9-12
- PubMed: 11432773 
- DOI: https://doi.org/10.1093/oxfordjournals.jbchem.a002967
- Primary Citation of Related Structures:  
1I3T, 1I47 - PubMed Abstract: 
To investigate the mutation mechanism of purine transition in DNA damaged with methoxyamine, a DNA dodecamer with the sequence d(CGCGAATTmo(4)CGCG), where mo(4)C is 2'-deoxy-N(4)-methoxycytidine, has been synthesized and its crystal structure determined. Two dodecamers form a B-form duplex. Electron density maps clearly show that one of the two mo(4)C residues forms a pair with a guanine residue of the opposite strand, the geometry being the canonical Watson-Crick type, and that the other mo(4)C residue forms a wobble pair with the opposite guanine residue. These two pairings are ascribed to the tautomerization of the methoxylated cytosine moieties between the amino and imino forms.
Organizational Affiliation: 
Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.