2．某些RNA有催化活性 1982年美国T. Cech等人发现四膜虫的rRNA前体 能在完全没有蛋白质的情况下进行自我加工，发现 RNA有催化活性 Thomas Cech University of Colorado at Boulder, USA
2．某些RNA有催化活性 1982年美国T. Cech等人发现四膜虫的rRNA前体 能在完全没有蛋白质的情况下进行自我加工，发现 RNA有催化活性 Thomas Cech University of Colorado at Boulder, USA
G-OH Right 2 exon Left exon GpU 3 Left exon Right exon 5 CUCUCU PA cUcUcUlpU 3 GGGAGG Spliced exons + Intron -OH3 GGGAGG SG PA 3 51 CUCUCU-OH GGGAGG G PA Figure The sequence of reactions in the self-splicing of Tetrahymena pre-rRNA.(1)The 3'-OH group of a guanine nucleotide attacks the GGGAGG intron's 5'-terminal phosphate to form a phosphodiester bond.displacing the 5'exon. (2)The newly generated 3'-OH group of the 5' Cyclized intron exon attacks the 5'-terminal phosphate of the 3' exon,thereby splicing the two exons and displac- ing the intron.(3)The 3'-OH group of the intron attacks the phosphate of the nucleotide that is 15 residues from the 5'end so as to cyclize the in- UUU-OH tron and displace its 5'-terminal fragment. Throughout this process,the RNA maintains a folded,internally hydrogen-bonded conformation that permits the precise excision of the intron
1983年美国S.Altman等研究RNaseP（由20%蛋 白质和80%的RNA组成），发现RNaseP中的RNA 可催化E. coli tRNA的前体加工。 Sidney Altman Yale University New Haven, CT, USA
1983年美国S.Altman等研究RNaseP（由20%蛋 白质和80%的RNA组成），发现RNaseP中的RNA 可催化E. coli tRNA的前体加工。 Sidney Altman Yale University New Haven, CT, USA
Primary transeript 3 OH OH RNase D cut OH 5 PGUUAUCAGUUAAUUGA RNase P eut Addition of CCA Splicing to 3 end Cleavage (a) (b) (c) OH OH Figure Processing of tRNAs in bacteria and 5 pC 5 sc- eukaryotes.The sequences shown in yellow are removed,(a)some by specific ribonucleases and Base (b)some by splicing reactions.(c)CCA is added to modification the 3'end in eukaryotic tRNAs and in those bacte- rial tRNAs that lack this sequence in the primary (d) transcript;this reaction is catalyzed by tRNA nu- cleotidyl transferase.(d)Finally,specific bases are modified (see Fig.25-25). Mature tRNA
Cech和Altman各自独立地发现了RNA的催 化活性，并命名这一类酶为ribozyme（核酶）， 2人共同获1989年诺贝尔化学奖。 1．Cell vol 31, 147～157，1982年。 2．Sci. Amer. Vol 255, 64～75，1986
Cech和Altman各自独立地发现了RNA的催 化活性，并命名这一类酶为ribozyme（核酶）， 2人共同获1989年诺贝尔化学奖。 1．Cell vol 31, 147～157，1982年。 2．Sci. Amer. Vol 255, 64～75，1986