Function of glycosyltransferase genes involved in urdamycin A biosynthesis.
BACKGROUND
Urdamycin A, the principle product of Streptomyces fradiae Tü2717, is an angucycline-type antibiotic. The polyketide-derived aglycone moiety is glycosylated at two positions, but only limited information is available about glycosyltransferases involved in urdamycin biosynthesis.


RESULTS
To determine the function of three glycosyltransferase genes in the urdamycin biosynthetic gene cluster, we have carried out gene inactivation and expression experiments. Inactivation of urdGT1a resulted in the predominant accumulation of urdamycin B. A mutant lacking urdGT1b and urdGT1c mainly produced compound 100-2. When urdGT1c was expressed in the urdGT1b/urdGT1c double mutant, urdamycin G and urdamycin A were detected. The mutant lacking all three genes mainly accumulated aquayamycin and urdamycinone B. Expression of urdGT1c in the triple mutant led to the formation of compound 100-1, whereas expression of urdGT1a resulted in the formation of compound 100-2. Co-expression of urdGT1b and urdGT1c resulted in the production of 12b-derhodinosyl-urdamycin A, and co-expression of urdGT1a, urdGT1b and urdGT1c resulted in the formation of urdamycin A.


CONCLUSIONS
Analysis of glycosyltransferase genes of the urdamycin biosynthetic gene cluster led to an unambiguous assignment of each glycosyltransferase to a certain biosynthetic saccharide attachment step.
Trefzer
A
A
Pharmazeutische Biologie, Universität Tübingen, Pharmazeutisches Institut, Tübingen, D-72076, Germany.
Hoffmeister
D
D
Künzel
E
E
Stockert
S
S
Weitnauer
G
G
Westrich
L
L
Rix
U
U
Fuchser
J
J
Bindseil
K U
KU
Rohr
J
J
Bechthold
A
A
D000617:Aminoglycosides; D000880:Anthraquinones / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000096:biosynthesis; D001426:Bacterial Proteins / Q000096:biosynthesis; D003001:Cloning, Molecular; D016368:Frameshift Mutation; D017353:Gene Deletion; D005822:Genetic Vectors / Q000096:biosynthesis; D016695:Glycosyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000737:chemistry / Q000235:genetics; D000095602:Angucyclines and Angucyclinones
D000617:Aminoglycosides; D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D000903:Antibiotics, Antineoplastic; D001426:Bacterial Proteins; D016695:Glycosyltransferases; C405923:urdamycinone B; C051487:urdamycin B; C000100:aquayamycin; D000095602:Angucyclines and Angucyclinones; C046608:kerriamycin B