title: Landomycins, new angucycline antibiotics from Streptomyces sp. I. Structural studies on landomycins A-D.
abstract: The chemical structure of the new angucycline antibiotic landomycin A has been elucidated via chemical and spectroscopic methods, in particular by 2D NMR correlation spectroscopy, e.g., 1H, 1H-COSY, 13C, 1H-COSY, correlation spectroscopy via long-range-couplings and heteronuclear multiple bond connectivity spectroscopy sequences. The spectroscopic investigations were carried out principally with the octaacetyl derivative of landomycin A, which is more soluble in organic solvents than landomycin A itself. The structure consists of a new, unusual angucyclinone, landomycinone A, and of six deoxy sugars, four D-olivoses and two L-rhodinoses, which are all assembled in one chain thus forming the sequence (olivose-4----1-olivose-3----1-rhodinose)2. This long sugar chain is bonded as a phenolic glycoside to the aglycone moiety, a unique structural feature among quinone glycoside antibiotics. By comparison with the main component landomycin A, the structures of three minor congeners, namely landomycins B, C and D, could be proposed.
authors.affiliation: Institut für Organische Chemie, Universität Göttingen, W. Germany.
authors.forename: T
authors.initials: T
authors.lastname: Henkel
authors.forename: J
authors.initials: J
authors.lastname: Rohr
authors.forename: J M
authors.initials: JM
authors.lastname: Beale
authors.forename: L
authors.initials: L
authors.lastname: Schwenen
mesh_terms: D000107:Acetylation; D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000302:isolation & purification; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002855:Chromatography, Thin Layer; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D013057:Spectrum Analysis; D013302:Streptomyces / Q000378:metabolism*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; C064648:landomycin A