Fig. 9

LC-ESI–MS/MS spectrum of the fengycin precursors. a Fengycin A precursors ion [M + H]⁺ at m/z 1479 at retention time 12.63 min containing a Glu1-Orn2-Tyr3-Thr4-Glu5-Ala6-Pro7-Gln8-Tyr9-Ile10 peptide and a C17 β-hydroxy fatty acid chain. b Fengycin A precursors ion [M + 2H]2⁺ at m/z 740 at retention time 12.69 min containing a C17 β-hydroxy fatty acid chain. c Fengycin B precursors ion [M + H]⁺ at m/z 1493 at retention time 12.92 min containing a Glu1-Orn2-Tyr3-Thr4-Glu5-Val6-Pro7-Gln8-Tyr9-Ile10 peptide and a C16 β-hydroxy fatty acid chain. d Fengycin B precursors ion [M + 2H]²⁺ at m/z 747 at retention time 13.15 min containing a C16 β-hydroxy fatty acid chain