Catalytic RNA has a quanosine-binding site 23.4 Ribozymes have sub strate-bin ding site 44 Guanosine binding site various catalytic Substrate binding activities Includes A&U First transfer G-OH occupies G-binding site;5' exon occupies substrate-binding site 4 -3 414 Figure 23.6 Excision of the group I intron in Tetrahymena 5 &8达S rRNA occurs by successive Second transfer G414 is in G-binding site:5' reactions between the occupants exon is in substrate-binding site CUCUCL 3 of the guanosine-binding site and substrate-binding site.The left 58为 GGGACO exon is red,and the right exon is Thrdraerisinbndingnd of intron is in substrate-binding site purple. 6 GGGAGG 清菜大当 -UUUACCU
Figure 23.6 Excision of the group I intron in Tetrahymena rRNA occurs by successive reactions between the occupants of the guanosine-binding site and substrate-binding site. The left exon is red, and the right exon is purple. 23.4 Ribozymes have various catalytic activities
23.4 Ribozymes have various catalytic activities First transfer g影9h8t9 oftacks G-OH 53 E如nA Exon B _3 DG-OH pN pNpNpN pN pN Figure 23.2 Self-splicing pNpNpNpNpN pN-OH occurs by pGpXpXpXpXpXpX transesterification Second transfer reactions in which bonds 多9H888n台aftacks are exchanged directly. The bonds that have been generated at each Third transfer stage are indicated by the 681o%8my shaded boxes. 情華大当
Figure 23.2 Self-splicing occurs by transesterification reactions in which bonds are exchanged directly. The bonds that have been generated at each stage are indicated by the shaded boxes. 23.4 Ribozymes have various catalytic activities