title: The guanosine binding mechanism of the Tetrahymena group I intron.
abstract: The Tetrahymena group I intron catalyzes self-splicing through two consecutive transesterification reactions, using a single guanosine-binding site (GBS). In this study, we constructed a model RNA that contains the GBS and a conserved guanosine nucleotide at the 3'-terminus of the intron (omegaG). We determined by NMR the solution structure of this model RNA, and revealed the guanosine binding mechanism of the group I intron. The G22 residue, corresponding to omegaG, participates in a base triple, G22 xx G3 x C12, hydrogen-bonding to the major groove edge of the Watson-Crick G3 x C12 pair. The G22 residue also interacts with A2, which is semi-conserved in all sequenced group I introns.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kitamura
authors.forename: Y
authors.initials: Y
authors.lastname: Muto
authors.forename: S
authors.initials: S
authors.lastname: Watanabe
authors.forename: I
authors.initials: I
authors.lastname: Kim
authors.forename: T
authors.initials: T
authors.lastname: Ito
authors.forename: Y
authors.initials: Y
authors.lastname: Nishiya
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuki
authors.forename: G
authors.initials: G
authors.lastname: Kawai
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Hosono
authors.forename: H
authors.initials: H
authors.lastname: Takaku
authors.forename: E
authors.initials: E
authors.lastname: Katoh
authors.forename: T
authors.initials: T
authors.lastname: Yamazaki
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000818:Animals; D020029:Base Pairing; D001483:Base Sequence; D001665:Binding Sites; D006151:Guanosine / Q000378:metabolism*; D006860:Hydrogen Bonding; D007438:Introns; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D016053:RNA, Protozoan / Q000737:chemistry* / Q000235:genetics*; D013768:Tetrahymena / Q000235:genetics*
chemical_list: D016053:RNA, Protozoan; D006151:Guanosine