Deoxysugar methylation during biosynthesis of the antitumor polyketide elloramycin by Streptomyces olivaceus
Fecha de publicación:
Editorial:
American Society for Biochemistry and Molecular Biology
Versión del editor:
Citación:
Descripción física:
Resumen:
The anthracycline-like polyketide drug elloramycin is produced by Streptomyces olivaceusTü2353. Elloramycin has antibacterial activity against Gram-positive bacteria and also exhibits antitumor activity. From a cosmid clone (cos16F4) containing part of the elloramycin biosynthesis gene cluster, three genes (elmMI, elmMII, andelmMIII) have been cloned. Sequence analysis and data base comparison showed that their deduced products resembledS-adenosylmethionine-dependentO-methyltransferases. The genes were individually expressed in Streptomyces albus and also coexpressed with genes involved in the biosynthesis of l-rhamnose, the 6-deoxysugar attached to the elloramycin aglycon. The resulting recombinant strains were used to biotransform three different elloramycin-type compounds: l-rhamnosyl-tetracenomycin C,l-olivosyl-tetracenomycin C, andl-oleandrosyl-tetracenomycin, which differ in their 2′-, 3′-, and 4′-substituents of the sugar moieties. When only the three methyltransferase-encoding genes elmMI, elmMII, and elmMIII were individually expressed in S. albus, the methylating activity of the three methyltransferases was also assayed in vitro using various externally added glycosylated substrates. From the combined results of all of these experiments, it is proposed that methyltransferases ElmMI, ElmMII, and ElmMIII are involved in the biosynthesis of the permethylatedl-rhamnose moiety of elloramycin. ElmMI, ElmMII, and ElmMIII are responsible for the consecutive methylation of the hydroxy groups at the 2′-, 3′-, and 4′-position, respectively, after the sugar moiety has been attached to the aglycon
The anthracycline-like polyketide drug elloramycin is produced by Streptomyces olivaceusTü2353. Elloramycin has antibacterial activity against Gram-positive bacteria and also exhibits antitumor activity. From a cosmid clone (cos16F4) containing part of the elloramycin biosynthesis gene cluster, three genes (elmMI, elmMII, andelmMIII) have been cloned. Sequence analysis and data base comparison showed that their deduced products resembledS-adenosylmethionine-dependentO-methyltransferases. The genes were individually expressed in Streptomyces albus and also coexpressed with genes involved in the biosynthesis of l-rhamnose, the 6-deoxysugar attached to the elloramycin aglycon. The resulting recombinant strains were used to biotransform three different elloramycin-type compounds: l-rhamnosyl-tetracenomycin C,l-olivosyl-tetracenomycin C, andl-oleandrosyl-tetracenomycin, which differ in their 2′-, 3′-, and 4′-substituents of the sugar moieties. When only the three methyltransferase-encoding genes elmMI, elmMII, and elmMIII were individually expressed in S. albus, the methylating activity of the three methyltransferases was also assayed in vitro using various externally added glycosylated substrates. From the combined results of all of these experiments, it is proposed that methyltransferases ElmMI, ElmMII, and ElmMIII are involved in the biosynthesis of the permethylatedl-rhamnose moiety of elloramycin. ElmMI, ElmMII, and ElmMIII are responsible for the consecutive methylation of the hydroxy groups at the 2′-, 3′-, and 4′-position, respectively, after the sugar moiety has been attached to the aglycon
Patrocinado por:
This work was supported by European Community Grant BIO4-CT96-0068 (to J. R. and J. A. S.), Spanish Ministry of Education and Science Grant BIO97-0771 through the “Plan Nacional en Biotecnologia” (to J. A. S.), and grants from the South Carolina Commission of Higher Education as well as the United States Department of Defense (to J. R.).
Colecciones
- Artículos [35715]