The guanosine binding mechanism of the Tetrahymena group I intron.
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.
Kitamura
A
A
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
Muto
Y
Y
Watanabe
S
S
Kim
I
I
Ito
T
T
Nishiya
Y
Y
Ohtsuki
T
T
Kawai
G
G
Watanabe
K
K
Hosono
K
K
Takaku
H
H
Katoh
E
E
Yamazaki
T
T
Inoue
T
T
Yokoyama
S
S
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*
D016053:RNA, Protozoan; D006151:Guanosine