TY - JOUR
T1 - Biosynthetic Studies on the Xanthone Antibiotics Lysolipins X and I
AU - Bockholt, Heike
AU - Udvarnoki, Györgyi
AU - Rohr, Jürgen
AU - Mocek, Ursula
AU - Beale, John M.
AU - Floss, Heinz G.
PY - 1994/4/1
Y1 - 1994/4/1
N2 - Feeding experiments with 13C and 18O-labeled precursors revealed that the molecular framework of the polycyclic xanthone antibiotics, the lysolipins X (1) and I (2), is derived from the polyketide pathway (12 malonate units), the C1 pool (methionine), molecular oxygen, and the nitrogen pool. Surprisingly, an intact malonate moiety serves as the three-carbon starter unit of the polyketide backbone, and 9 of the 12 oxygen atoms of 1 originate from molecular oxygen, including both of the xanthone oxygen atoms. The orientation of the malonate unit incorporated intact into lysolipin is unique and opposite from those in tetracycline and cycloheximide, i.e., the activated carbon of malonyl CoA is bound to the nitrogen of the lysolipin isoquinoline ring and the CO2-derived carbon serves as the starter of the polyketide chain. From the biogenetic origin of the oxygen atoms several unusual prearomatic deoxygenation steps early in the biosynthesis have to be postulated.
AB - Feeding experiments with 13C and 18O-labeled precursors revealed that the molecular framework of the polycyclic xanthone antibiotics, the lysolipins X (1) and I (2), is derived from the polyketide pathway (12 malonate units), the C1 pool (methionine), molecular oxygen, and the nitrogen pool. Surprisingly, an intact malonate moiety serves as the three-carbon starter unit of the polyketide backbone, and 9 of the 12 oxygen atoms of 1 originate from molecular oxygen, including both of the xanthone oxygen atoms. The orientation of the malonate unit incorporated intact into lysolipin is unique and opposite from those in tetracycline and cycloheximide, i.e., the activated carbon of malonyl CoA is bound to the nitrogen of the lysolipin isoquinoline ring and the CO2-derived carbon serves as the starter of the polyketide chain. From the biogenetic origin of the oxygen atoms several unusual prearomatic deoxygenation steps early in the biosynthesis have to be postulated.
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U2 - 10.1021/jo00087a021
DO - 10.1021/jo00087a021
M3 - Article
AN - SCOPUS:0000489059
SN - 0022-3263
VL - 59
SP - 2064
EP - 2069
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 8
ER -