A gene cluster from Streptomyces galilaeus involved in glycosylation of aclarubicin

Abstract

We have cloned and characterized a gene cluster for anthracycline biosynthesis from Streptomyces galilaeus. This cluster, 15-kb long, includes eight genes involved in the deoxyhexose biosynthesis pathway, a gene for a glycosyltransferase and one for an activator, as well as two genes involved in aglycone biosynthesis. Gene disruption targeted to the activator gene blocked production of aclacinomycins in S. galilaeus. Plasmid pSgs4, containing genes for a glycosyltransferase (aknS), an aminomethylase (aknX), a glucose-1-phosphate thymidylyltransferase (akn Y) and two genes for unidentified glycosylation functions (aknT and aknV), restored the production of aclacinomycins in the S. galilaeus mutants H063, which accumulates aklavinone, and H054, which produces aklavinone with rhodinose and deoxyfucose residues. Furthermore, pSgs4 directed the production of L-rhamnosyl-epsilon-rhodomycinone and L-daunosaminyl-epsilon-rhodomycinone in S. peucetius strains that produce epsilon-rhodomycinone endogenously. Subcloning of the gene cluster was carried out in order to further define the genes that are responsible for complementation and hybrid anthracycline generation.

Glycogenomics as a mass spectrometry-guided genome-mining method for microbial glycosylated molecules

“…Coclustered with the deoxysugar biosynthesis gene locus were genes predicted for aglycone biosynthesis comprising an aromatic type II polyketide synthase (PKS). Further analysis of the gene set revealed its similarity to the aclacinomycin gene cluster from Streptomyces galileus (41,42). This enabled the classification of the target compound as a glycosylated anthracycline polyketide.…”

Natural‐Product Sugar Biosynthesis and Enzymatic Glycodiversification

“…Although the gene clusters for both aclarubicin [77] and rhodomycin [96] have been partially sequenced, genes for these activities have not been assigned in either cluster. l-Oleandrose (77) is found in the macrolide antibiotic oleandomycin produced by Streptomyces antibioticus and in avermectin produced by Streptomyces avermitilis.…”

“…The encoded enzymes likely catalyze the corresponding steps in both sugar biosynthetic pathways. [62] The sugars l-nogalamine (52), [22] l-daunosamine (see 53), [76] and l-rhodosamine (see 54) [77] are found in the anthracycline antibiotics nogalamycin, daunorubicin, and aclarubicin, respectively. Their common precursor is 60, which undergoes 3,5-epimerization and stereospecific ketoreduction in each pathway.…”

Isolation, Characterization, and Heterologous Expression of the Biosynthesis Gene Cluster for the Antitumor Anthracycline Steffimycin

“…This has prompted the study of this family of natural products to the level of their biosynthesis in order to develop new bioactive compounds by recombinant DNA technology (33). In particular, three anthracycline compounds have been studied so far: daunorubicin-doxorubicin (18), nogalamycin (59,56), and aclacinomycin (42,43). These studies have revealed the assembly of this type of compound by type II polyketide synthases (PKS) that consist of several discrete proteins carrying a set of iteratively used enzyme activities.…”