The fractions were analyzed sequentially on a Q Exactive HF Hybrid Quadrupole-Orbitrap Mass Spectrometer (Thermo Scientific) coupled to an UltiMate 3000 RSLCnano ultra HPLC system (Thermo Scientific) and EasySpray column (75µm × 50 cm, PepMap RSLC C18 column, 2µm, 100Å, Thermo Scientific). Buffers A (0.1% formic acid in water) and B (0.08% formic acid in 80% acetonitrile) were used over a linear gradient from 5 to 35% buffer B over 125 min at 300nL min -1 . The column temperature was 50°C. The mass spectrometer was operated in data dependent mode with a single mass spectrometry survey scan from 335-1,600 m/z followed by 15 sequential m/z dependent MS2 scans. The 15 most intense precursor ions were sequentially fragmented by higher energy collision dissociation. The MS1 isolation window was set to 0.7 m/z and the resolution set at 120,000. MS2 resolution was set at 60,000. The automatic gain control (AGC) targets for MS1 and MS2 were set at 3 × 10 6 ions and 1 × 10 5 ions, respectively. The normalized collision energy was set at 32%. The maximum ion injection times for MS1 and MS2 were set at 50 and 200 ms, respectively.