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Structure investigation of Maltacine D1a, D1b and D1c—cyclic peptide lactones of the Maltacine complex from Bacillus subtilis
Author(s) -
Hagelin Gunnar
Publication year - 2005
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.897
Subject(s) - chemistry , peptide , stereochemistry , cyclic peptide , residue (chemistry) , bacillus subtilis , ring (chemistry) , lactone , amino acid , organic chemistry , biochemistry , bacteria , biology , genetics
A new complex of cyclic peptide lactone antibiotics from Bacillus subtilis , which we named Maltacines has recently been described. The structure elucidation of three of them is reported in this paper. The amino acid sequences and structures of the peptides were found by MS n of the ring‐opened linear peptides that gave uninterrupted sequences of B n and Y″ n ions. The identities of four unknown residues in the sequences were solved by a combination of derivatisation with phenylisothiocyanate (PITC), high‐resolution mass spectrometry and H/D exchange. The nature and position of the cyclic structure was disclosed by a chemo‐selective ring opening with Na 18 OH and was found to be a lactone formed between a hydroxyl of residue number 4 and the C ‐terminal amino acid number 12. For verification of the structure of the B 2 + ion, peptides with different combinations of P/Q and P/K at the N ‐terminus were synthesized. The structures of the four peptides is tentatively suggested to be: D1a: cyclo(4,12)‐P‐Q‐Y‐Adip‐A‐E‐T‐Y‐Orn‐HGly‐Y‐I‐OH, D1b: cyclo(4,12)‐P‐Q‐Y‐Adip‐A‐E‐T‐Y‐Orn‐S‐Y‐I‐OH and D1c: cyclo(4,12)‐P‐Q‐Y‐Adip‐A‐E‐T‐Y‐K‐S‐Y‐I‐OH. Adip = aminodihydroxy pentanoic acid and HGly = hydroxyglycine. Copyright © 2005 John Wiley & Sons, Ltd.