Practice question

Spliceosome is one of largest cellular complexes, megadalton machine composed of five small nuclear ribonucleoproteins snRNPs U1, U2, U4, U5, U6, each containing uridine-rich snRNA, ring of seven Sm or LSm proteins, and particle-specific proteins. Together snRNPs provide RNA-RNA recognition, catalytic core via U6 snRNA forming active site similar to group II self-splicing introns, and protein scaffold stabilizing conformations. Spliceosome undergoes extensive compositional remodeling driven by eight DEAH/D-box helicases Prp2, Prp5, Prp16, Prp22, Prp43, Brr2, allowing progression through E, A, B, Bact, C complexes culminating in exon ligation and proofreading.