Kemptide

Acetonitrile, BCA protein assay kit, methanol, ethanol and 10 x PBS were purchased from Thermo Scientific (Waltham, MA, USA). Triethylammonium bicarbonate (TEAB), formic acid, Kemptide, dithiothreitol, Carbonate-Bicarbonate buffer capsules and Tween 20 were purchased from Sigma-Aldrich (St Louis, MO, USA). BSA was purchased from Bovogen (Victoria, Australia). M-280 Tosyl Activated Dynabeads were purchased from Invitrogen Dynal (Oslo, Norway). The recombinant fusion protein standards for α-Conotoxin VxXXc, α-Cobratoxin and α-Bungarotoxin as well as the negative control fusion proteins His and Myc tagged SUMO (Small Ubiquitin-like Modifier) and His and Myc tagged GST (Glutathione S-Transferase) were purchased from My BioSource (San Diego, USA). The sequences for the recombinant proteins are presented in supplementary figure 1. Sequencing grade trypsin was purchased from Promega (Madison, WI, USA). Peptides (Table 1) were custom synthesized by Auspep (Tullamarine, Australia) and prepared as 1 mg/mL stocks in 20% ethanol, before being stored as 200 µL aliquots at -70°C. All aqueous buffers were prepared in Milli Q Synergy grade water (Billerica, MA, USA). 10-well Mini Protean TGX stain free Any kD gradient Gels, 10x Tris/Glycine/SDS running buffer and Precision plus protein standards were all purchased from Bio-Rad (Hercules, CA, USA)