Fig. 5. SmB binds to Csul and Vls. Left panel: GST-Csul and GST-Vls proteins stained with Coomassie Blue. Middle panel: [³⁵S]S^*Tag-SmB fragments were separated by SDS-PAGE and detected by fluorography. Right panel: Following incubation with GST-Csul or GST-Vls, the bound [³⁵S]S^*Tag-SmB fragments were separated and detected as described above. No binding was detected with GST alone (data not shown). Below these panels the binding results of SmB and derivatives as well as those of SmD1 and SmD3 to Csul and Vls are summarized graphically. Size and structure of the SmB, SmD1 and SmD3 proteins are depicted with the two Sm domains and the RG dipeptides shown as orange boxes and circles, respectively. N- and C-terminal amino acid residues of the Sm proteins and fragments are indicated.