Biosynthetic Origin of the Oxygen Atoms of Tetracenomycin C

摘要

There is currently great interest in the details of the polyketide biosynthetic pathway, one of nature's most important routes for forming a diversity of bioactive compounds. For the past few years we have focused our attention on polycyclic. aromaticpolyketides. so-called type II polyketides. Recent investigations of the sources of oxygen in the metabolites have provided novel insights, for example, unexpected deoxygenation steps before aromatization during the general assembly of these polyketides. The tetracenomveins (e.g. tetracenomycin C (1)) and elloramycins (e.g. elloramycin A (2)) form a small, distinct group of tetracyclic. aromatic polyketides whose biosyntheses have been extensively studied. Nevertheless, the oxygena-tion reactions, thelast steps of the biosynthesis of tetracenomycin C (1) from its immediate precursor tetracenomycin A, (3). are not well understood and are still subjects of debate. We describe here the biosynthetic sources of all the oxygen atoms of tetracenomycin C (1) and. to our knowledge, the first experimental proof in biosynthetic studies of an oxygen atom derivine from H_2O.