title: Conformational analysis of d(C3G3), a B-family duplex in solution.
abstract: NMR and circular dichroism studies of the duplex formed by the self-complementary DNA hexanucleotide d(C3G3) indicate that it is a B-type structure but differs from standard B-form. An analysis of NMR coupling constants within the deoxyribose moieties yields a 70% or greater contribution from pseudorotation phase angles corresponding to the C3'-exo conformation, a conformation similar to the C2'-endo conformation associated with B-form DNA. Intranucleotide interproton distances are consistent with a B-form structure, but some internucleotide distances are intermediate between A- and B-form structures. Circular dichroism spectra have B-form characteristics but also include an unusual negative band at 282 nm. The solution spectroscopic results are in contrast with X-ray crystallographic studies which find A-form structures for similar sequences.
authors.affiliation: Department of Chemistry, University of California, Berkeley 94720.
authors.forename: S
authors.initials: S
authors.lastname: Wolk
authors.forename: W N
authors.initials: WN
authors.lastname: Thurmes
authors.forename: W S
authors.initials: WS
authors.lastname: Ross
authors.forename: C C
authors.initials: CC
authors.lastname: Hardin
authors.forename: I
authors.initials: I
authors.lastname: Tinoco
mesh_terms: D002942:Circular Dichroism; D004247:DNA; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D012996:Solutions
chemical_list: D009838:Oligodeoxyribonucleotides; D012996:Solutions; D004247:DNA