Conformational rearrangement of the spliceosomal complex containing the RNA products from the 1st step of splicing to form the catalytic site for the second step of splicing.
synonyms:
formation of catalytic U2-type spliceosome for second transesterification step,
lariat formation, 5'-splice site cleavage,
catalytic spliceosome assembly for second transesterification step,
spliceosomal A2-3 complex formation,
formation of spliceosomal A2-2 complex,
spliceosomal C2 complex formation,
GO:0000358,
spliceosomal C2 complex biosynthesis,
formation of spliceosomal C1 complex,
spliceosomal A2-3 complex biosynthesis,
formation of catalytic spliceosome for second transesterification step,
GO:0000359,
formation of catalytic U12-type spliceosome for second transesterification step
