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Fig. 21 Comparison of characterized and cryptic cytochalasan gene clusters. Abbreviations:
pDA = putative Diels-Alderase, trans-ER = trans enoyl reductase, OXR = oxidoreductase/monooxygenase, CYP = cytochrome P450, BMVO = Baeyer–Villiger monooxygenase, OMT
= O-methyltransferase, OAT = O-acetyltransferase, TF = transcription, factor/transcriptional
regulator, MFS = transporter
silencing of CheA, which resulted in the production of chaetoglobosin A (208) and
chaetoglobosin C (210) being nearly entirely abolished.
In the fungus Chaetomium globosum, the second gene cluster for chaetoglobosin
A (208) biosynthesis was characterized (Fig. 21C) [259]. By means of BLASTP of
the previously characterized hybrid proteins CheA in the genome of C. globosum,
a homologous PKS–NRPS protein encoded by CHGG_01239 was identified, which
showed an amino acid sequence identity and similarity of 34.3% and 52.2% to CheA,
respectively. Neighboring this PKS-NRPS was a trans-ER encoded by the gene
CHGG_01240. Similar to P. expansum, the chaetoglobosin A (208) biosynthetic gene