MS characterization of spidroin-1

For MS characterization of major ampullate spidroin-1 from the three species of Nephila clavipes, edulis and madagascariensis, an experimental approach was developed combining 2-DE with multiple proteolytic in-gel digestion (trypsin, chymotrypsin, pepsin, proteinase K, subtilisin and proteinase 10) followed by NanoLC and mass spectrometry analysis using collision-induced dissociation (CID) and electron-transfer dissociation (ETD) for fragmentation. MASCOT searches were done by using the MASCOT 2.2.06 (Matrix Science, London, UK) against database for protein identification and post-translational modifications.