FIGURE 2.

Cross-linking results using BS³ chemical reaction. (A) A 150-μM peptide solution is mixed without (c) and with (xl) BS³ cross-linker. Multiple bands in a lane with cross-linker indicate that homooligomeric forms exist in solution. The MultiMark prestained protein standard was used. (B) Cross-linking experiment showing peptide-peptide association of NK₄-M2GlyR p22 S22W in both water and 40% TFE solution at a high concentration (3 mM). The Mark12 unstained protein standard was used. Note: silver staining intensities with these small peptides is somewhat variable. Loaded samples with matched concentrations can, on occasion, show different dye binding affinities particularly when cross-linked (see Fig. 2 A). Cross-linked monomer shows reduced staining intensity relative to that observed for the oligomeric assemblies that have more dye binding sites. The gels shown are representative of multiple cross-linking experiments and polyacrylamide gel electrophoresis analyses.