Fig. 2.

Association between Sin1p and Fir1p peptides in vitro. GST or GST/Sin1p bacterially produced fusion proteins were immobilized on 200-μl glutathione agarose beads. Fir1p peptides labeled with [³⁵S]methionine were produced in the Promega TNT-coupled transcription-translation system. Ten microliters of the reaction was incubated with the glutathione agarose beads. After washing, bound proteins were eluted with glutathione, and three-quarters of the eluted volume was subjected to SDS/PAGE and autoradiography. The multiple bands represent partial Fir1p molecules that result from premature transcriptional and translational termination, internal transcriptional initiation, and RNA and protein degradation. The arrow shows the full-length protein.