The carbazomycin-producing microorganism, strain H 1051-MY 10, was determined to a strain of Streptoverticillhan ehimense. Biosynthesis of carbazomycin B was studied using 1}C-labeled and 13C-enriched precursors in combination with 13C NMR spectroscopy. The C-2 carbon of [2-13C]tryptophan was shown to be involved at the C-3 carbon in carbazomycin B and both carbons of [ 1,2-"C] acetate at the C-1 and C-10 moiety of the antibiotic. [CH,-13C]Methionine was involved at the methoxyl group but not at the methyl group on the C-2 carbon of the antibiotic. Neither of the labeled carbons, [1-1'C]tryptophan nor [2,3-11C]propionic acid , was detected in the antibiotic, and a progenitor of the C-2 and C-11 moiety of the antibiotic has not been determined. Carbazomycins A and B were produced by an unidentified microorganism, tentatively designated as strain H 1051-MY 10. Carbazomycins inhibited mainly the growth of phytopathogenic fungi and also showed weak antibacterial and antiyeast activities'). The structure of carbazomycin B (I) was determined to be 4-hydroxy-3-methoxy-l,2-dimethylcarbazole by 1H and 13C NMR spectral) and by X-ray crystallographic analysis'). Consequently, the structure of carbazomycin A (II) was postulated to be
Streptomycin 6-kinase of the streptomycin-producing strain Streptomyces griseus HUT 6037 was purified by fractionation with (NH&SO, and chromatography on DEAE-Sephadex A-25, hydroxyapatite and Sephadex G-100. After PAGE of the final fraction, a protein band corresponding to streptomycin 6-kinase was detected, together with a less intense band having no enzyme activity. Molecular weights determined by SDS-PAGE and by Sephadex G-100 chromatography were about 36000 and 38000, respectively, suggesting that the enzyme was a monomer. The isoelectric point of the enzyme was pH 6.6. Among the nucleoside 5'-triphosphates tested, ATP was the preferred phosphoryl donor. The K , values for streptomycin and ATP were 3.5 mM and 0.4 mM, respectively. The enzyme activity was strongly inhibited by EDTA and AgNO,. It was shown by using an in vitro protein-synthesizing system that purified streptomycin 6-kinase could protect polyphenylalanine synthesis of the streptomycinsusceptible S . griseus strain KSN from inhibition by streptomycin.
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