「音」を単元とした音楽科と図画工作科との合科による協働授業の試み : 「土笛づくり」を中心に(2.教員養成における教育実践,vi 教員養成と教師教育)

Thiopeptins are highly decorated thiopeptide antibiotics similar in structure to thiostrepton A and harbor two unusual features. All thiopeptins contain a thioamide, a rare moiety among natural products, and a subset of thiopeptins present with a piperidine in the core macrocycle rather than the more oxidated dehydropiperidine or pyridine rings typically observed in the thiopeptides. Here, we report the identification of the thiopeptin biosynthetic gene ( tpn) cluster in Streptomyces tateyamensis and the gene product, TpnL, which shows sequence similarity to (deaza)flavin-dependent oxidoreductases. Heterologous expression of TpnL in the thiostrepton A producer Streptomyces laurentii led to the production of a piperidine-containing analogue. Binding studies revealed that TpnL preferentially binds the deazaflavin cofactor coenzyme F₄₂₀, and in vitro reconstitution of TpnL activity confirmed that this enzyme is an F₄₂₀H₂-dependent dehydropiperidine reductase. The identification of TpnL and its activity establishes the basis for the piperidine-containing series a thiopeptides, one of the five main structural groups of this diverse family of antibiotics.