10.12.6 Terpestacin
Four genes for the biosynthesis of terpestacin (77) have been identified in the
genome from the fungus Bipolaris maydis [132, 154]. One of the four genes encodes
a sesterterpene synthase that produces 175. The other three genes encode oxidases,
two cytochrome P450s, and a single flavin-dependent oxidase. These oxidases could
convert 175 into 176, 177, 178, and 77 (Fig. 122).
11 Conclusions
This contribution provides an overview of the chemical structures of
sesterterpenoids. Even though only relatively few sesterterpenoids are known,
their structures are quite fascinating. In particular, the complexity of polycarbocyclic
sesterterpenoids is quite high. There are many stereocenters in their structures, and
their stereochemistry is well controlled during the cyclization reactions leading to the
formation of their basic carbon skeletons. Moreover, many sesterterpenoids are
known as bioactive compounds.
HO
OH
HO
COOH
HO
OH
HO
8
OH
OH
OH
HO
O
O
OH
HO
O
OH
P450
P450
P450
FAD
oxidase
175
176
177
178
77
Fig. 122 Structures and formation of 175–178, and 77. The structure of 77 is also shown in Fig. 53
70
T. Mitsuhashi and I. Abe