Structural investigation of cyclic peptidolipids fromBacillus subtilis by high-energy tandem mass spectrometry

Abstract

The natural products belonging to the surfactin family are cycloheptapeptides bearing a long β‐hydroxy‐fatty acyl chain at the N‐terminal position. The structure of these compounds, often isolated as complex mixtures, can be elucidated by high‐energy tandem mass spectrometry (MS/MS). The protonated molecules generated by cesium ion bombardment (LSIMS) undergo charge‐proximate fragmentations leading to the b‐ and y‐type ion series useful for the sequence determination. The sodium‐cationised molecules show a radically different behaviour towards high‐energy collisional activation. Besides the well‐known charge‐remote dissociation products of the alkyl side chain, complete series of d‐ and w‐type fragments allow easy distinction between leucine and isoleucine. The complementary MS/MS data obtained from the protonated and cationised molecules prove to be of great interest for the structural characterisation of this type of compounds. Copyright © 2001 John Wiley & Sons, Ltd.

Bacillus subtilis subsp. subtilis CBMDC3f with antimicrobial activity against Gram-positive foodborne pathogenic bacteria: UV-MALDI-TOF MS analysis of its bioactive compounds

“…Moreover, common peaks ions as the internal protonated fragment ion [(H)Leu 2 -Leu 3 -Val 4 -Asp 5 -Leu 6 -Leu/Ile 7 (OH) ?H] ? ,were in both cases also detected (Hue et al 2001;Tang et al 2010;Pathak and Keharia 2014. In conclusion, B. subtilis subsp subtilis CBMDC3f presented a broad spectrum of inhibitory activity against L. monocytogenes, B. cereus and S. aureus, all of them foodborne pathogens. Surfactin, iturin and fengycin were detected in the CFS, whereas only surfactin predominated in the LF; this suggests that the applied extraction method recovered mainly surfactin homologues.…”

Identification and quantification of lichenysin – a possible source of food poisoning

“…This is in accordance with the findings of Yakimov et al 1999 (Yakimov et al, 1999). y6 after dehydration at the N-terminal end, m/z 685.45, is by far the most abundant fragment ion from all precursors and represents the peptide moiety after ring opening and loss of the fatty acid chain and AA1 (Hue et al 2001, Yakimov et al, 1999. The elucidated amino acid sequence for all three major peaks was the same: Gln -Leu/Ile -Leu/Ile -Val -Asp -Leu/Ile -Leu/Ile.…”

Review of surfactin chemical properties and the potential biomedical applications

“…Hydrophobic amino acid residues are located at positions 2, 3, 4, 6 and 7, while the glutamyl and aspartyl residues at position 1 and 5, respectively, introduce two negative charges to the molecule. Several surfactin isoforms usually coexist in the cell as a mixture of several peptidic variants [16,17] with a different aliphatic chain length [18].…”