Mass Spectrometric Deconvolution of Nonribosomally Synthesized Microbial Microheterogeneous Lipopeptide Library

摘要

LC-ESI-MSn facilitated identification of several new surfactin and fengycins from B. subtilis K1 and B. tequilensis P15. Total 60 novel fngycins based on variation at four positions, 1) N-terminus β-OH Chain length, 2) position 6 (Ala/ Val/ Ile/ Leu), 3) position 10 (Val/Ile) and 4) position 8(Glu/Gln) were identified from B. subilis K1. Diagnostic product ions provided quick method of identification of various classes of fengycins. Linearization of fengycins by mild alkali treatment permitted fragmentation of fengycins for identification of novel fengycins. The esterification of fengycins with benzyl alcohol provided quick identification of fengycins varying by 1Da. High resolution mass spectrometry facilitated localization of 1Da variation in fengycins. 37 new surfactins based on the variations at 1) N-terminus N- terminus β-OH Chain length, 2) position 4 (Val/Ile/Leu), 3) position 5 (Asp/ Omet-Asp/Leu/Ile), 4) position 6 (Asp/Leu/Ile) and 5) position 7 (Leu/Ile/Val) could be identified.