A New Siderophore Isolated from Streptomyces sp. TM‐34 with Potent Inhibitory Activity Against Angiotensin‐Converting Enzyme

Abstract

A new siderophore named tsukubachelin was isolated from an iron-deficient culture medium of newly isolated strain Streptomyces sp. TM-34. The chemical structure of tsukubachelin was established by the interpretation of 2D NMR and TOF-Mass spectroscopic data. The structure of tsukubachelin consists of six amino acid residues, including three serine, and one each of N-α-methyl-N-δ-hydroxy-N-δ-formylornithine, N-α-methyl-N-δ-hydroxyornithine, and cyclic Nhydroxyornithine. Because the structurally related sidero-

A 4-tert-butylcalix[4]arene tetrahydroxamate podand based on the 1-oxypiperidine-2-one (1,2-PIPO−) chelate. Self-assembly into a supramolecular ionophore driven by coordination of tetravalent zirconium or hafnium(iv)

“…1), a six-membered cyclic hydroxamic acid that is found as third, pendent binding unit in a few number of siderophores such as exochelin MN 7 and tsukubachelin. 8 Structural studies revealed as expected the formation of tetraleptic complexes with tetravalent d-and f-block elements, including Zr 4+ , Ce 4+ , Hf 4+ , Th 4+ , and U 4+ . 3g As the binding sites of 1,2-PIPO À are incorporated in a cyclic structure similarly to 1,2-HOPO À , the former is also a ligand preorganized for chelation, therefore its complexes should be more stable than those originating from linear hydroxamates which prevail in solution in their E or trans form.…”

Structure and biosynthesis of scabichelin, a novel tris-hydroxamate siderophore produced by the plant pathogen Streptomyces scabies 87.22

“…TM-34 and TM-74. 41,42 Scabichelin was shown to be the metabolic product of a cryptic nonribosomal peptide biosynthetic gene cluster identified within the S. scabies 87.22 genome. Sequence analysis of this gene cluster indicated that scabichelin functions as a siderophore and prompted us to hypothesize that an unusual bi-functional epimerizationcondensation domain catalyses release of scabichelin from the NRPS responsible for its biosynthesis, resulting in the formation of its cyclic D-hydroxyornithine residue.…”

Effects of trace metal ions on secondary metabolism and the morphological development of streptomycetes

“…This siderophore is structurally related to desferri-foroximithine, a compound with a potent angiotensin-converting enzyme inhibition activity. 72 The structurally related siderophore tsukubachelin B was also isolated under limited iron conditions from the strain Streptomyces sp. TM-74.…”