期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：13
页码：4390-4395
DOI：10.1073/pnas.0400277101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Chloroeremomycin, a vancomycin family glycopeptide antibiotic has three sugars, one D-glucose and two L-4-epi-vancosamines, attached to the crosslinked heptapeptide backbone by three glycosyltransferases, GtfA, -B, and -C. Prior efforts have revealed that GtfB and -C in tandem build an epivancosaminyl-1,2-glucosyldisaccharide chain on residue 4 of the aglycone; however, the characterization of GtfA and glycosylation sequence of chloroeremomycin have been lacking. Here, we report the expression and purification of GtfA, as well as synthesis of its sugar donor, 2'-deoxy-thymidine 5'-diphosphate (dTDP)-{beta}-L-4-epi-vancosamine. GtfA transfers 4-epi-vancosamine from the chemically synthesized dTDP-4-epi-vancosamine to the {beta}-OH-Tyr6 residue of the aglycone, preferentially after GtfB action, to generate chloroorienticin B. With the preferred kinetic order of GtfB, then GtfA, then GtfC established, we have succeeded in reconstitution of chloroeremomycin from the heptapeptide aglycone by the sequential actions of the three enzymes.
