Figure 9.

LC-MS/MS analysis of P. paxilli paxD deletion mutant. (a) UV trace at 275 nm of extract of P. paxilli wild-type; (b) Single ion extracted (504.3 m/z) chromatograms for wild-type and paxD deletion mutant; (c) Collision-induced fragmentation spectrum of the 504.3 m/z ion from wild-type (average of 6 mass spectra). Key ions are 488.3 (loss of CH₄), 486.3 (loss of H₂O), which is similar to paxilline fragmentation and 198.2 (prenylated indole). Based on these spectra, we assume that the prenylation occurs on the indole part of the molecule. However, the exact location of the prenyl group on the indole system remains to be elucidated.