Fig. 2. Purification of proteins that bind to R1 and R2. These are gels of the proteins that bind to R1 and R2 affinity columns, stained with Coomassie Blue. The DimB and DimB' proteins were identified by mass spectrometry. Several of the other proteins, selected by both R1 and R2, are RNA-binding proteins. The asterisked species is MybE (M.F. and J.G.W., unpublished).