title: Conformation of a bulge-containing oligomer from a hot-spot sequence by NMR and energy minimization.
abstract: Two-dimensional nmr data on a bulge-containing oligodeoxyribonucleotide, 5'dGATGGGCAG.dCTGACCCATC, and a regular oligomer of similar sequence, 5'dGATGGCAG.dCTGCCATC, are presented. The nonexchangeable protons are assigned from sequential nuclear Overhauser effect spectroscopy (NOESY) connectivities. The two-dimensional NOE (NOESY) and correlated (COSY) spectra of the bulge-containing oligomer are compared to those of the perfect 8-mer. Experimental proton-proton distances are determined from NOESY spectra acquired with mixing times of 100, 150, and 200 ms, using comparable distances in the B-DNA region of the molecule as a calibration. With this approach, measured distances do not depend systematically on mixing time. Energy minimization techniques are used to calculate a three-dimensional structure for the bulge-containing oligomer in agreement with the nmr data. The helix is of the B family, with the extra adenine stacked into the helix, and the helix axis is bent by 20 degrees.
authors.forename: S A
authors.initials: SA
authors.lastname: Woodson
authors.forename: D M
authors.initials: DM
authors.lastname: Crothers
mesh_terms: D001483:Base Sequence; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides; D013816:Thermodynamics
chemical_list: D009838:Oligodeoxyribonucleotides