Biology And Biomedical Sciences BIOL 2960 Lecture 32: RNA Splicing Mechanism
12 Apr 2017
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Document Summary
Splicing doesn"t require ntp hydrolysis, but does require enzyme activity. Multiple rna/protein complexes: snrnp"s (u1, u2, u4, u5, u6) Splicing begins with 5" splicing site (gu) recognition by u1 snrna found in the u1 snrnp (small nuclear ribonucleoprotein) Protein complex binds to the 3" splicing site (ag) U2 binds to the branch point (a) forming part of the catalytic center. U4, u5, and u6 recruited together: u4 and u6 are joined (u4 is a scaffold snrnp) U5 binds the 5" ss, then the 3" ss. U4 masks the catalytic activity of u6, delivering it to the spliceosome. Rna centric view splicing is a mostly rna catalyzed reaction. U1 rna sequence is complementary to the 5" ss consensus. U2 rna sequence is complementary to the sequences flanking the branch point. U5 rna binds to exon sequences and holds them together. U4 and u6 are paired together u4 delivers u6, then leaves.
