title: Spectroscopic studies on the interaction of pradimicin BMY-28864 with mannose derivatives.
abstract: Pradimicin BMY-28864 (Pm) is an antibiotic effective against yeasts and fungi, and is known to bind mannose in the presence of Ca2+. We examined spectroscopically the mode of interactions among Pm, Ca2+, and glycosides of mannose and mannose oligosaccharides (Manalpha1-OMe, Manalpha1-2Manalpha1-OMe, Manalpha1-3Manalpha1-OMe, Manalpha1-4Manalpha1-OMe, Manalpha1-6Manalpha1-OMe, Manalpha1-6(Manalpha1-3)Manalpha1-OMe, and Man9GlcNAc2-Asn, a high mannose type N-linked oligosaccharide). All the mannosides interacted with Pm in the presence of Ca2+ and caused absorbance changes. The absorbance changes occurred nonlinearly with respect to the carbohydrate concentration and do not follow a simple binding isotherm equation, suggesting a unique multistep interaction mode. The concentrations that induced half the maximum absorbance change were approximately 10 mM for the mono- and di-mannosides and around 1.5 mM for the trimannoside and Man9GlcNAc2-Asn. Methyl alpha-D-glucopyranoside, methyl alpha-D-galactopyranoside, lactose, and myo-inositol did not affect the absorbance of Pm up to 50 mM. Ca2+ alone also influenced the absorbance of Pm. The absorbance between 200 and 700 nm decreased hypochromically when Ca2+ was added. The concentration that gave half the maximum absorbance decrease caused by Ca2+was around 15 microM. Our results suggest that two Pm molecules bind one C a2+, and each Pm binds two mannosyl residues.
authors.affiliation: Department of Biology, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA.
authors.forename: K
authors.initials: K
authors.lastname: Fujikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Tsukamoto
authors.forename: T
authors.initials: T
authors.lastname: Oki
authors.forename: Y C
authors.initials: YC
authors.lastname: Lee
mesh_terms: D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic / Q000378:metabolism* / Q000494:pharmacology*; D000935:Antifungal Agents / Q000378:metabolism* / Q000494:pharmacology*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002240:Carbohydrate Sequence; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism; D046911:Macromolecular Substances; D008358:Mannose / Q000378:metabolism*; D008362:Mannosides / Q000737:chemistry / Q000378:metabolism; D008766:Methylmannosides / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic; D000935:Antifungal Agents; D006027:Glycosides; D046911:Macromolecular Substances; D008362:Mannosides; D008766:Methylmannosides; D009844:Oligosaccharides; C028569:oligomannoside; C067714:N,N-dimethylpradimicin FA-2; C008466:methylmannoside; D008358:Mannose; D002118:Calcium