Figure 4.

Limited proteolysis patterns for Sec2p and Sec2-78p purified from yeast (NY2432 and NY2438, respectively) are different. Trypsin digestion was allowed to proceed for 5 min, aliquots were withdrawn at t = 0 s, 30 s, 60 s, 2.5 min, and 5 min. Proteolytic fragments were detected with αGST (top) and αSec2p (middle) antibodies and by silver staining of an SDS-PAGE gel (bottom). Both antibodies recognize the N-terminal part of GST-Sec2p and show the same pattern. GST-Sec2 truncated proteins purified from yeast were included (middle) for size comparison with the proteolytic fragments.