title: Crystal structure of a four-stranded intercalated DNA: d(C4).
abstract: The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Cai
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: A
authors.initials: A
authors.lastname: Rich
mesh_terms: D003196:Computer Graphics; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA