Crystal structure of a group I ribozyme domain: principles of RNA packing.
Group I self-splicing introns catalyze their own excision from precursor RNAs by way of a two-step transesterification reaction. The catalytic core of these ribozymes is formed by two structural domains. The 2.8-angstrom crystal structure of one of these, the P4-P6 domain of the Tetrahymena thermophila intron, is described. In the 160-nucleotide domain, a sharp bend allows stacked helices of the conserved core to pack alongside helices of an adjacent region. Two specific long-range interactions clamp the two halves of the domain together: a two-Mg2+-coordinated adenosine-rich corkscrew plugs into the minor groove of a helix, and a GAAA hairpin loop binds to a conserved 11-nucleotide internal loop. Metal- and ribose-mediated backbone contacts further stabilize the close side-by-side helical packing. The structure indicates the extent of RNA packing required for the function of large ribozymes, the spliceosome, and the ribosome.
Cate
J H
JH
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA. doudna@csb.yale.edu
Gooding
A R
AR
Podell
E
E
Zhou
K
K
Golden
B L
BL
Kundrot
C E
CE
Cech
T R
TR
Doudna
J A
JA
D000225:Adenine / Q000737:chemistry; D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007438:Introns; D008274:Magnesium / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010710:Phosphates / Q000737:chemistry; D010802:Phylogeny; D012326:RNA Splicing; D016337:RNA, Catalytic / Q000737:chemistry* / Q000378:metabolism; D016053:RNA, Protozoan / Q000737:chemistry* / Q000378:metabolism; D012266:Ribose / Q000737:chemistry; D016808:Tetrahymena thermophila / Q000235:genetics
D010710:Phosphates; D016337:RNA, Catalytic; D016053:RNA, Protozoan; D012266:Ribose; D008274:Magnesium; D000225:Adenine