Sedimentation behavior and protein composition of CDC5/Prp19-containing complexes. Complexes were immunoaffinity purified from HeLa nuclear extract with anti-CDC5 antibodies and subjected to 5–20% glycerol gradient centrifugation. Proteins from uneven fractions were separated by SDS–PAGE and stained with Coomassie. The following proteins (indicated with arrows) were identified by MS: CDC5 (NP_001244), HSP73 (NP_006588), β-catenin-like 1 (NP_110517), PRL1 (NP_002660), Prp19 (NP_055317), AD002 (AAF14858), SPF27 (NP_005863), Npw38 (NP_005701), and Npw38BP (NP_057396).