Geminal Bismethylation Prevents Polyketide Oxidation and Dimerization in the Benastatin Pathway

Abstract

Nicht methyliert, sondern dimerisiert: Eine enzymatische geminale Bismethylierung blockiert in der Biosynthese des zytotoxischen Polyketids Benastatin die hoch reaktive Benzylposition eines Anthron‐Intermediats. Eine Mutante ohne diese C‐Methyl‐Transferase bildet Chinone sowie komplizierte meso‐ und rac‐Dimere (siehe berechnete Struktur), die mit spektroskopischen Methoden und Computersimulationen analysiert wurden.

Die biosynthetische Grundlage der Polyketid‐Vielfalt

“…[112,113] Die hoch reaktive Benzylposition von Anthronen neigt zur spontanen radikalvermittelten Dimerisierung, wie für verwandte Polyphenole nachgewiesen wurde. [114] Schema 20. Oxidative Umlagerung von Angucyclinen führt zu Strukturvielfalt.…”

{Sn10[Si(SiMe3)3]5}– : An Anionic Metalloid Tin Cluster from an Isolable SnI Halide Solution

“…The open ligand shell also leads to directly accessible tin atoms as to be seen from the space filling model in Figure 2, giving the opportunity to apply 5 as a building block in subsequent reactions, as it was lately possible for the anionic metalloid germanium cluster {Ge 9 [Si(SiMe 3 ) 3 ] 3 } -, where the nine germanium atoms are also incompletely shielded by the ligands. [18] However, 5 exhibits only one open side and will therefore react in a different way.…”

Ketosynthase III as a gateway to engineering the biosynthesis of antitumoral benastatin derivatives

“…Fermentation, extraction, and HPLC monitoring were conducted as described previously (Lackner et al, 2007;Schenk et al, 2007;Xu et al, 2007). Relative production rates were estimated by integration of peaks.…”