Although the chemical structure of spore pigments in streptomycetes is
unknown, the biosynthesis of these pigments is encoded by type II
polyketide synthases similar to those of the aromatic polyketides. (A
deviation of this pathway is involved in enterocin biosynthesis.) In
collaboration with Prof. David Hopwood (John Innes Institute),
Prof. Heinz Floss (University of Washington), and Prof. Chaitan Khosla
(Stanford University), we expressed incomplete gene sets of the whiE
(spore pigment) cluster from Streptomyces coelicolor and other
homologous gene clusters from other streptomycetes. Chemical analysis
of the resulting metabolites provided clues to the nature of the spore
pigment and to the function of the polyketide synthase and its
tailoring enzymes.
Structures of the characterized minimal whiE PKS
products TW93a-h
(many additional uncharacterized products remain unsolved) and of the
minimal whiE PKS plus whiE cyclase ORFVI products TW95a
and TW95b.
