P-93 Actinorhodin生合成後期修飾過程における酸素導入に関する新たな知見(ポスター発表の部)

概要

論文の詳細を見る
Actinorhodin (ACT) produced by Streptomyces coelicolor A3(2) is a member of benzoisochromanequinone (BIQ) antibiotics. ActVA-6 has been suggested to be involved in oxygenation at C-6 position of BIQs. However, actVA-6 homologous genes could not been found in the other BIQ clusters and instead actVA-5-type oxygenase genes are commonly present. This study deals with the possible contribution of actVA-5, actVA-6 and related actVB genes in ACT biosynthesis. A deletion mutant of the actVA-6 gene (ΔactVA-6) produced almost comparable amount of ACT compared with wild type strain, whereas ΔactVA-5,6 abolished ACT production and yielded a novel dimeric shunt product, actinoperylone (ACPL), with two chiral centers at C-3 and C-15 of each monomeric unit. Production of ACPL was also demonstrated by the introduction of the minimal gene sets for 6-deoxy-dihydrokalufungin (DDHK) in S. coelicolor act-deficient mutant. All these results demonstrate the critical role of ActVA-5 in C-6 oxygenation and derivation of its substrate DDHK from (S)-DNPA by ActVI-2 catalyzed stereospecific enoylreduction at C-15. Although Valton et al recently proposed that ActVA-5/ActVB is a two-component flavin-dependent monooxygenase system introducing the oxygen at C-8 of dihydrokalufungin (DHK), an essentially similar assay conditions converted emodinanthrone, a model substrate for C-6 oxygenation, into emodin. The same activity was detected with ActVA-6 but with less efficiency. Deletion of actVB resulted in the simultaneous production of ACT and ACPL, indicating that the C-6 oxygenation in vivo is indeed affected by the disorder in ActVA-5/ActVB system. In summary, the present study concludes that C-6 oxygenation is primarily catalyzed by the ActVA-5/ActVB system in ACT biosynthesis.
天然有機化合物討論会の論文
2008-09-01

P-93 Actinorhodin生合成後期修飾過程における酸素導入に関する新たな知見(ポスター発表の部)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク