title: Effects of Cosolvents on the Folding and Catalytic Activities of the Hammerhead Ribozyme.
abstract: The RNA cleavage activity of the hammerhead ribozyme has been compared in various mixed aqueous solutions containing cosolvents. Kinetic analysis revealed that the tested cosolvents enhanced the ribozyme activity, particularly at low MgCl2 concentrations. These enhancements, in some cases of more than tenfold, resulted from a reduction in the Mg(2+) concentration required for substrate cleavage. An inverse correlation was found between the MgCl2 concentration essential for efficient catalysis and the dielectric constant values. In contrast, FRET measurements showed no substantial influence of cosolvents on the Mg(2+) -induced structural transitions. The results suggest that the solution environment has various effects on the Mg(2+) interactions involved in the catalysis and global folding of the ribozyme.
authors.affiliation: Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan). shuichi@center.konan-u.ac.jp.
authors.forename: Shu-ichi
authors.initials: S
authors.lastname: Nakano
authors.affiliation: Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan).
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kitagawa
authors.affiliation: Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan).
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yamashita
authors.affiliation: Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan).
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miyoshi
authors.affiliation: Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan).|Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047 (Japan).
authors.forename: Naoki
authors.initials: N
authors.lastname: Sugimoto
mesh_terms: D004789:Enzyme Activation / Q000187:drug effects; D007477:Ions; D015636:Magnesium Chloride / Q000737:chemistry / Q000494:pharmacology*; D008958:Models, Molecular; D017510:Protein Folding / Q000187:drug effects; D016337:RNA, Catalytic / Q000378:metabolism*; D012997:Solvents / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D007477:Ions; D016337:RNA, Catalytic; D012997:Solvents; C427204:hammerhead ribozyme; D015636:Magnesium Chloride
keywords: FRET; RNA base-pairs; kinetics; melting temperatures; ribozymes; solvent effects