By a combination of chemical and spectroscopic (XH and 13C NMR)studies the structure of a glycopeptide antibiotic eremomycin has been elucidated. It is closely related to vancomycin, but differs in sugar and chlorine content. The eremomycinaglycone contains monodechlorovancomycinic acid; the only chlorine atom is situated in the second amino acid after the TV-terminal amino acid residue of the peptide. The sugar part is composed of glucose and two residues of an amino sugar shown to be 2,3,6-trideoxy-3-amino-C-3-methyl-L-flraZ?z>2o-hexopyranose (4-/?/-vancosamine). One of the amino sugar residues is a component of the disaccharideglucopyranose, attached to a triphenyl ether moiety; the position of another one is at the serine oxygen in the C-terminal region of the aglycone.Eremomycin is identical to the recently obtained antibiotic A82846Aand is very similar to orienticin A but differs from it only in the position of a chlorine. Eremomycinwas isolated from the culture filtrate of actinomycete numbered INA-238 by means of an ion exchange technique1}. Taxonomic studies of the producing culture will be published elsewhere. Eremomycinwas obtained as a homogenouscrystalline sulfate and on the basis of its chemical and biological properties was identified as a new memberof the vancomycin group of antibiotics2).
A new chiral stationary phase (CSP) was prepared by attachment of macrocyclic glycopeptide antibiotic eremomycin to the epoxy-activated silica under mild conditions. In contrast to CSP with immobilized vancomycin, which is a close structural analogue of eremomycin, the prepared CSP reveals high enantioselectivity for separation of amino acids enantiomers. It was demonstrated by the example of ristocetin A CSP that method of the immobilization of macrocyclic glycopeptide antibiotics affects remarkably the resulting enantioselectivity.
We describe the actinomycete strain IMV-70 isolated from the soils of Kazakhstan, which produces potent antibiotics with high levels of antibacterial activity. After the research of its morphological, chemotaxonomic, and cultural characteristics, the strain with potential to be developed further as a novel class of antibiotics with chemotherapeutics potential was identified asStreptomycessp. IMV-70. In the process of fermentation, the strainStreptomycesspp. IMV-70 produces the antibiotic no. 70, which was isolated from the culture broth by extraction with organic solvents. Antibiotic compound no. 70 was purified and separated into individual components by HPLC, TLC, and column chromatography methods. The main component of the compound is the antibiotic 70-A, which was found to be identical to the peptolide etamycin A. Two other antibiotics 70-B and 70-C have never been described and therefore are new antibiotics. The physical-chemical and biological characteristics of these preparations were described and further researched. Determination of the optimal growth conditions to cultivate actinomycete-producer strain IMV-70 and development of methods to isolate, purify, and accumulate preparations of the new antibiotic no. 70 enable us to research further the potential of this new class of antibiotics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.