Rationally designed glycosylated premithramycins: hybrid aromatic polyketides using genes from three different biosynthetic pathways.
Heterologous expression of the urdGT2 gene from the urdamycin producer Streptomyces fradiae Tü2717, which encodes a C-glycosyltransferase, into mutants of the mithramycin producer Streptomyces argillaceus, in which either one or all glycosyltransferases were inactivated, yielded four novel C-glycosylated premithramycin-type molecules. Structure elucidation revealed these to be 9-C-olivosylpremithramycinone, 9-C-mycarosylpremithramycinone, and their respective 4-O-demethyl analogues. In another experiment, both the urdGT2 gene from S. fradiae and the lanGT1 gene from S. cyanogenus, were coexpressed into a S. argillaceus mutant lacking the MtmGIV glycosyltransferase. This experiment, in which genes from three different organisms were combined, resulted in the production of 9-C-(olivo-1-4-olivosyl)premithramycinone. These results prove the unique substrate flexibility of the C-glycosyltransferase UrdGT2, which tolerates not only a variety of sugar-donor substrates, but also various acceptor substrates. The five new hybrid products also represent the first compounds, in which sugars were attached to a position that is normally unglycosylated. The successful combination of two glycosyltransferases in the latter experiment proves that the design of saccharide side chains by combinatorial biosynthetic methods is possible.
Trefzer
Axel
A
Albert-Ludwigs-Universität Freiburg im Breisgau, Pharmazeutische Biologie, Stefan-Meier Strasse 19, 79104 Freiburg, Germany.
Blanco
Gloria
G
Remsing
Lily
L
Künzel
Eva
E
Rix
Uwe
U
Lipata
Fredilyn
F
Braña
Alfredo F
AF
Méndez
Carmen
C
Rohr
Jürgen
J
Bechthold
Andreas
A
Salas
José A
JA
D000903:Antibiotics, Antineoplastic / Q000096:biosynthesis*; D006027:Glycosides / Q000096:biosynthesis*; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D008926:Plicamycin / Q000031:analogs & derivatives* / Q000096:biosynthesis; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics*
D000903:Antibiotics, Antineoplastic; D006027:Glycosides; D016695:Glycosyltransferases; D008926:Plicamycin