Cwc2 in yeast is a NTC-associated protein that integrates into the spliceosome. It is the only associated protein to acquire RNA binding domains, and aid in the spatial arrangement of the spliceosome’s catalytic core. The Cwc2 crystal structure led to the discovery of three vital domains: Torus, RRM and ZnF, and UV-induced cross-linking studies allowed for the identification of the 6 RNA-contacting sites, inevitably terming this factor as a “multi-partite RNA-binding protein.”
