Fig. 4.

Structure of C₁₅ surfactin. Main cleavage site in MS/MS fragments and amino acid composition of C₁₅ surfactin (a). Predicted b- and y-ion fragment lists of C₁₅ surfactin (b). Positive ion MS/MS spectrum of C₁₅ surfactin (m/z 1036.69) (c) and negative ion MS/MS spectrum of C₁₅ surfactin (m/z 1034.68) (d)