Application of Fast Atom Bombardment Combined with Tandem Mass Spectrometry to the Structural Elucidation ofO-demethylabierixin and Related Polyether Antibiotics

Abstract

O-Demethylabierixin, a new polyether antibiotic, was isolated from a Streptomyces spp. Its structure elucidation was carried out with fast atom bombardment mass spectrometry (FAB-MS) and fast atom bombardment mass spectrometry-mass spectrometry (FAB-MS/MS) by comparing spectral patterns with those of structurally similar polyether compounds, nigericin and abierixin. The collision-induced dissociation (CID) of sodium-adduct and deprotonated molecular ions produced many cyclic ether rings-opened product ions via a series of the dissociative processes. Because of the negative charge of the carboxylate group at the end of the molecule, the charge-remote fragmentation pattern in the negative CID spectra of deprotonated molecular ions was very helpful for complete identification of product ions which are characteristic for cyclic ether structures. From this study, the new polyether antibiotic was identified to be O-demethylabierixin in which the methoxy group of six-membered ether ring in abierixin was replaced by the hydroxy group.

Fragmentation study of salinomycin and monensin A antibiotics using electrospray quadrupole time‐of‐flight mass spectrometry

“…The molecular structures of the compounds investigated here are displayed in Scheme , which shows the labeled ether rings and the backbone carbon atoms. According to a nomenclature for ionophore antibiotics suggested by Kim et al .,22 fragment ions containing the terminal carboxyl group of the molecule or the terminal hydroxyl group were named as type A or type F ions, respectively.…”

Applications and mechanisms of charge-remote fragmentation

“…Naoki, Murata and Yasumoto (1993) and Havlicek, Ryska and Pospisil (1995) used tandem mass spectrometry to characterize successfully the structures of natural polycyclic ethers. Recently, Kim et al (1996) studied nigericin (13), abierixin (14), and O-demethylabierixin (15) by FAB-MS/ MS. Although CA of the [M Na] and [M À H] À ions produces suf®cient information for structural determination, the CAD spectrum of the [M À H] À is easier to interpret.…”

Influence of the alkali metal cation on the fragmentation of monensin in ESI-MS/MS

“…Monensin A (C 36 H 60 O 10 , 670 Da) is the most investigated polyether by low-resolution mass (Schen, Brodbelt, 2000;Kiehl et al, 1998;Kim et al, 1996;Volmer, Lock, 1998;Lopes et al, 2001Lopes et al, , 2002aLopes et al, , 2002b. The high affinity for Na + and K + ions usually limits these studies to the sodiated complex.…”