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Biochemistry. 2004 Apr 20;43(15):4548-58.

AknK is an L-2-deoxyfucosyltransferase in the biosynthesis of the anthracycline aclacinomycin A.

Author information

1
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.

Abstract

The antitumor drug aclacinomycin A is a representative member of the anthracycline subgroup that contains a C(7)-O-trisaccharide chain composed of L-2-deoxysugars. The sugar portion of the molecule, which greatly affects its biological activity, is assembled by dedicated glycosyltransferases; however, these enzymes have not been well-studied. Here we report the heterologous expression and purification of one of these enzymes, AknK, as well as the preparation of dTDP-L-2-deoxysugar donors, dTDP-L-2-deoxyfucose and dTDP-L-daunosamine, and the monoglycosyl aglycone, rhodosaminyl aklavinone. Our experiments show that AknK catalyzes the addition of the second sugar to the chain, using dTDP-L-2-deoxyfucose and rhodosaminyl aklavinone, to create the L-2-deoxyfucosyl-L-rhodosaminyl aklavinone. AknK also accepts an alternate dTDP-L-sugar, dTDP-L-daunosamine, and other monoglycosylated anthracyclines, including daunomycin, adriamycin, and idarubicin, to build alternate disaccharides on variant anthracycline backbones. Remarkably, AknK also catalyzes a tandem addition of a second L-2-deoxyfucosyl moiety, albeit with reduced activity, to the natural disaccharide chain to produce L-deoxyfucosyl-L-deoxyfucosyl-L-rhodosaminyl aklavinone, a variant of the natural aclacinomycin A. These results demonstrate that AknK may be a useful enzyme for the chemoenzymatic synthesis of anthracycline variants.

PMID:
15078101
DOI:
10.1021/bi035945i
[Indexed for MEDLINE]

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