spliceosome conformational change to release U4 (or U4atac) and U1 (or U11)
spliceosome conformational change to release u4 (or u4atac) and u1 (or u11)
U12-type spliceosome conformational change to release U4atac and U11
u12-type spliceosome conformational change to release u4atac and u11