title: New reactions catalyzed by a group II intron ribozyme with RNA and DNA substrates.
abstract: Here we describe three novel reactions of the self-splicing group II intron bI1 (the first intron of the COB gene of yeast mitochondria) demonstrating its catalytic versatility: reversal of the first step of the self-splicing reaction catalyzed by a linear form of the intron utilizing the energy of a phosphoanhydride bond for transesterification, ligation of a single-stranded DNA to an RNA, and cleavage of a single-stranded DNA substrate. These results have the following evolutionary implications: use of the alpha-beta bond of a terminal triphosphate for transesterification suggests that an RNA RNA replicase could use mononucleotide triphosphates as precursors, and cleavage of single-stranded DNA and DNA-RNA ligation suggests that excised group II introns might integrate directly into DNA without prior reverse transcription.
authors.affiliation: Institut für Genetik und Mikrobiologie, Universität München, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Mörl
authors.forename: I
authors.initials: I
authors.lastname: Niemer
authors.forename: C
authors.initials: C
authors.lastname: Schmelzer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D004247:DNA / Q000378:metabolism*; D007438:Introns; D008969:Molecular Sequence Data; D012313:RNA / Q000378:metabolism*; D012326:RNA Splicing; D016337:RNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D016337:RNA, Catalytic; D012313:RNA; D004247:DNA