Two different peptides were produced: Sys and Sys-scramble (Scp), the latter was used as control. Peptides synthesis, purification and stability are described elsewhere [40 (link)]. Briefly, the peptides were obtained by solid phase synthesis following standard protocols [41 (link)]. Purification of the peptides was carried out by Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) (Shimadzu LC-8A, equipped with a SPD-M10 AV) on a semipreparative column (Jupiter 10µProteo 90A, 250 × 10.0 mm, Phenomenex, Torrance, CA, USA) using a gradient of acetonitrile (0.1% TFA) in water (0.1% TFA) from 5 to 50% in 30 min at 5 mL/min. Peptides were characterized by mass spectrometry (LC-MS ESI-TOF 6230 Agilent Technologies, Milan, Italy). Systemin sequence: AVQSKPPSKRDPPKMQTD. Mass calculated: 2009.3 Mass found: 670.94 [M + 3H]3+; 1005.60 [M + 2H]2+.
Systemin scramble sequence: KSKMDRQPVQAPDKPSPT. Mass calculated: 2009.3 Mass found: 670.96 [M + 3H]3+; 1005.53 [M + 2H]2+.
Peptide stability was tested as previously described [40 (link)]. Analysis of the HPLC (Shimadzu LC-8A, equipped with a SPD-M10 AV) profiles and of the mass spectra collected indicates that the peptide is stable in all the tested conditions [40 (link)]. Stock solutions of the synthesized peptides were prepared as described in [42 ].
Systemin scramble sequence: KSKMDRQPVQAPDKPSPT. Mass calculated: 2009.3 Mass found: 670.96 [M + 3H]3+; 1005.53 [M + 2H]2+.
Peptide stability was tested as previously described [40 (link)]. Analysis of the HPLC (Shimadzu LC-8A, equipped with a SPD-M10 AV) profiles and of the mass spectra collected indicates that the peptide is stable in all the tested conditions [40 (link)]. Stock solutions of the synthesized peptides were prepared as described in [42 ].