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 Coloradoan
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-0 ert exon G 3 Left exon 5 CUCUCU PA Right exon 5 CUCUCUPU GGGAGG Spliced exons GGGAGG G 3 5 CUCUCU-OH ApUU GGGAGG Fi The sequence of reactions in the self-splicing of Tetrahymena pre-rRNA. (1) The 3-OH group of a guanine nucleotide attacks the GGGAGG introns 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 LoH 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 transcript 3 OH RNase d cut 5 5 PGUUAUCAQUUAAUUG AACCGA Cleavage ACOG A (e) Figure Processing of tRNAs in bacteria and 5 eukaryotes. The sequences shown in yellow are removed,(a) some by specific ribonucleases and by spli (c) CCA is added to modification AACCG AU ccCG C CCG the 3 end in eukaryotic tRNAs and in those bacte- GGGCG AGGC 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Aman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 vol31,147-157,1982年 2.Sci.Amer.Vol255.64~75,1986
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