Fig. 5

MS/MS de novo sequencing identified m/z 1022.6732 (C₅₃H₉₃N₇O₁₃) as [Leu⁷] surfactin C₁₅. Purple arrows show changes in fragment m/z due to loss of the indicated amino acids from the full-length molecule. Red arrows show changes in fragment m/z due to addition of the indicated amino acids, starting from the di-leucine fragment at m/z 227.1751