title: Additional hydrogen bonds and base-pair kinetics in the symmetrical AMP-DNA aptamer complex.
abstract: The solution structure of an adenosine monophosphate (AMP)-DNA aptamer complex has been determined previously [Lin, C. H., and Patel, D. J. (1997) Chem. Biol. 4:817-832]. On a symmetrical aptamer complex containing the same binding loop, but with better resolved spectra, we have identified two additional hydrogen bond-mediated associations in the binding loop. One of these involves a rapidly exchanging G imino proton. The phosphate group of the AMP ligand was identified as the acceptor by comparison with other aptamer complexes. Imino proton exchange measurements also yielded the dissociation constants of the stem and binding loop base pairs. This study shows that nuclear magnetic resonance-based imino proton exchange is a good probe for detection of weak hydrogen-bond associations.
authors.affiliation: Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. sn@pmcsun1.polytechnique.fr
authors.forename: S
authors.initials: S
authors.lastname: Nonin-Lecomte
authors.forename: C H
authors.initials: CH
authors.lastname: Lin
authors.forename: D J
authors.initials: DJ
authors.lastname: Patel
mesh_terms: D000249:Adenosine Monophosphate / Q000737:chemistry*; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010710:Phosphates / Q000737:chemistry; D011522:Protons; D012313:RNA / Q000737:chemistry; D013997:Time Factors
chemical_list: D008024:Ligands; D010710:Phosphates; D011522:Protons; D000249:Adenosine Monophosphate; D012313:RNA; D004247:DNA