Immobilization of GST-S-B fusion on syntaxin beads. (A) Coomassie-stained gel showing retention of the recombinant GST-S-B fusion on syntaxin beads at indicated times. (B) Graph showing activity of GST-S-B attached to syntaxin beads measured by the increase in absorbance at 340 nm due to conjugation of glutathione to 1-chloro-2,4-dinitrobenzene. The data show mean +/- standard deviation, n = 3. (C) Coomassie-stained gel showing that syntaxin beads can be regenerated following a wash with 2% SDS, 20 mM HCl for binding of the S-B three-helical protein. (D) The ability of syntaxin beads to bind S-B in presence of calf serum is shown in this pull-down experiment. Coomassie-stained gel. (F) Specific binding of the FITC labelled syntaxin peptide to glutathione beads with GST-S-B immobilized in presence of calf serum.