New antiviral antibiotics, kistamicins A and B. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

The structures of antiviral antibiotics kistamicins A and B have been determined by a combination of chemical degradation and spectral analysis. They are commonly composed of D-tyrosine, 3, 5-dihydrophenylglycine, a biphenyl ether bis-amino acid, and a diphenyl substituted indole tris-amino acid, forming a tricyclic ring structure. Kistamicin B possessed a phenethylamide at the amino terminal of kistamicin A. They are structurally related to the nuclei of the vancornycin group antibiotics particularly to antibiotic complestatin.