title: Protein facilitation of group I intron splicing by assembly of the catalytic core and the 5' splice site domain.
abstract: The yeast mitochondrial group I intron b15 undergoes self-splicing at high Mg2+ concentrations, but requires the splicing factor CBP2 for reaction under physiological conditions. Chemical accessibility and UV cross-linking experiments now reveal that self-processing is slow because functional elements are not properly positioned in an active tertiary structure. Folding energy provided by CBP2 drives assembly of two RNA domains that comprise the catalytic core and meditates association of an approximately 100 nt 5' domain that contains the 5' splice site. Thus, the protein assembles RNA secondary structure elements into a specific three-dimensional array while the RNA provides the catalytic center. The division of labor between RNA and protein illustrated by this simple system reveals principles applicable to complex ribonucleoprotein assemblies such as the spliceosome and ribosome.
authors.affiliation: Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder 80309-0215, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Weeks
authors.forename: T R
authors.initials: TR
authors.lastname: Cech
mesh_terms: D001483:Base Sequence; D002384:Catalysis; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D007438:Introns; D007700:Kinetics; D008928:Mitochondria / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012326:RNA Splicing; D012331:RNA, Fungal / Q000096:biosynthesis* / Q000737:chemistry; D012261:Ribonucleoproteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: C071249:CBP2 protein, S cerevisiae; D005656:Fungal Proteins; D012331:RNA, Fungal; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins