title: Solution structure of Fe(II)-azide-bleomycin derived from NMR data: transition from Fe(II)-bleomycin to Fe(II)-azide-bleomycin as derived from NMR data and structural calculations.
abstract: The coordination cage of the metal center in Fe(II)-bleomycin has been proposed to consist of the secondary amines in β-aminoalanine, the pyrimidinylpropionamide and imidazole rings, and the amide nitrogen in β-hydroxyhistidine as equatorial ligands, and the primary amine in β-aminoalanine and either the carbamoyl group in mannose or a solvent molecule occupying the axial sites. With the aim of supporting or not supporting coordination of a water molecule to the metal center in Fe(II)-bleomycin, the solution structure of Fe(II)-azide-bleomycin has been derived from NMR data. The structural changes that occur in Fe(II)-bleomycin upon azide binding have been monitored by comparing the experimental results with those obtained from the calculated structures for both bleomycin adducts. The results of this investigation strongly support a model of Fe(II)-bleomycin with six endogenous ligands as the most likely structure held in solution by this metallobleomycin in the absence of DNA.
authors.affiliation: Department of Chemistry, University of Wyoming, Laramie, WY 82071, USA. tlehmann@uwyo.edu
authors.forename: Teresa
authors.initials: T
authors.lastname: Lehmann
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D001761:Bleomycin / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013302:Streptomyces / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000903:Antibiotics, Antineoplastic; D001386:Azides; D005296:Ferrous Compounds; D014867:Water; D001761:Bleomycin