The intron is removed in a Form callled a lariat(套马索)as o the Flanking Exons are joined u) Two successive transesterification a hthe branch site attacks the da 3 Step 1: The OH of the conserve o at t phoryl group of the conserved in the 5, splice site. As a result, the 5 exon is released and the send of the e. intron forms a three-way 总 Junction structure
The intron is removed in a Form Called a Lariat (套马索) as the Flanking Exons are joined Two successive transesterification: Step 1: The OH of the conserved A at the branch site attacks the phosphoryl group of the conserved G in the 5’ splice site. As a result, the 5’ exon is released and the 5’-end of the intron forms a three-way junction structure. The chemistry of RNA splicing
Figure 13-3 5 exon intron 3’exon 5 AP GPGPU A PAPG⊙G3 OH2′ Three-way junction 5P GHOH 3 PA LPAPGPIG 3
Figure 13-3 Three-way junction
The structure of three-way junction Intron O=P-O 5’end 5 end of intron o-CH2 base CH O OH Fiqure 13-4 O=P-O O OH 3’end of intron Copyright 2004 Pearson Education, Inc, publishing as Benjamin Cummings This figure has an error
The structure of three-way junction Figure 13-4 This figure has an error Intron 5’ end
Step 2: The OH of the 5 exon attacks the phosphoryl group at the 3' splice site. As a consequence, the 5 and 3' exons are joined and the intron is liberated in the shape of a lariat
Step 2: The OH of the 5’ exon attacks the phosphoryl group at the 3’ splice site. As a consequence, the 5’ and 3’ exons are joined and the intron is liberated in the shape of a lariat
5 PGOH3′ A APGPIG 3 Figure 13-3 eAAG+5■PGG3 /G intron lariat spliced exons Copyright o 2004 Pearson Education, Inc, publishing as Benjamin Cummings
Figure 13-3