Mutations in a semiconserved region of the Tetrahymena intron.
The A-rich bulge in paired region P5a of the Tetrahymena intron is a structural feature that is conserved in the sub-group Ib self-splicing introns. We have constructed a series of substitution and deletion mutations in this region of the intron. Kinetic analysis has shown that some of the mutants have a reduced maximal extent of splicing, while others have a reduced Vmax. These mutations could be reactivated to a great extent by spermidine and high Mg2+ concentrations. These data are consistent with the hypothesis that the A-rich bulge of P5a has a role in stabilizing the higher-level structure of the ribozyme.
Pace
U
U
Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Szostak
J W
JW
D000818:Animals; D001483:Base Sequence; D007438:Introns; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D012326:RNA Splicing; D016337:RNA, Catalytic / Q000737:chemistry*; D013095:Spermidine / Q000494:pharmacology; D013768:Tetrahymena / Q000187:drug effects / Q000235:genetics*
D016337:RNA, Catalytic; D008274:Magnesium; D013095:Spermidine