L. Colombo et al., CONTRIBUTION OF MASS-SPECTROMETRY TO THE STRUCTURAL CONFIRMATION OF COMPONENTS OF THE ANTIBIOTIC GE2270 COMPLEX, Rapid communications in mass spectrometry, 9(8), 1995, pp. 717-722
The GE2270 complex consists mainly of GE2270 A (MW 1289), a thiazolyl
peptide antibiotic whose structure originates from the modification of
a chain of 14 amino acids in a process which creates six thiazole rin
gs and one pyridine. Together with the main component, a number of str
ucturally related molecules are co-produced in small quantities by fer
mentation. A preparative high-performance liquid chromatrography metho
d was developed to isolate GE2270 factors B-1, B-2, C-1, C-2a, C-2b, D
-1, D-2, E and T. Their structures, preliminarily determined by H-1-nu
clear magnetic resonance spectroscopy in comparison with GE2270 A, wer
e confirmed by low and high resolution fast-atom bombardment mass spec
trometry and studies on the intact molecules and on their main hydroly
sis products. Their molecular weights range from 1246 to 1306 Da. The
structural differences between the factors lie in the extent of methyl
ation and/or oxidation of thiazole rings (D and E) and asparagine, and
in the aromatization of the oxazoline ring.