Streptomyces cacaoi Polyoxins

The octosyl acids are isolated from Streptomyces cacaoi they are part of a broader group of polyoxin antifungal nucleosides [349]. Danishefsky and co-workers [350] have reported a total synthesis of octosyl acid A featuring the hetero-Diels-Alder addition of ( )-l-methoxy-3-(trimethylsilyloxy)butadiene to a protected D-ribose-derived aldehyde. 

Polyoxin antibiotics were discovered in Japan in cultures of Streptomyces cacaoi var. asoensis (Suzuki et al., 1965). They are a mixture of related components with similar physical and chemical properties. The structure of polyoxins (15, 16) was elucidated by Isono et al. (1969). That, for example, of polyoxin B was found to be... 

Polyoxins constitute a group of antifungal metabolites produced by Streptomyces cacaoi var. asoensis, the gross structure of which is divisible into a nucleoside moiety and a dipeptide comprised of a unique functionalized polyhydroxynorvaline known commonly as 5-(9- or d-... 

Nucleoside antibiotics with a bicyclic carbohydrate unit from Streptomyces cacaoi var. asoensis. Distinctions are made between O. A (pK i 3.0 pKj2 4.3 pKg3 9.4), O. B, and O. C(pK, 3.1 pK 24.5 pK,j 9.9). 0. represent a large group of polyoxin-like antibiotics with antifungal activities. 

Figure 4.4 Schematic representation of the genetic organization of the polyoxin biosynthetic gene cluster from Streptomyces cacaoi.

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