Görner Christian, Hirte Max, Huber Stephanie, Schrepfer Patrick, Brück Thomas
Fachgebiet für Industrielle Biokatalyse, Department für Chemie, Technische Universität München Garching, Germany.
Front Microbiol. 2015 Oct 13;6:1115. doi: 10.3389/fmicb.2015.01115. eCollection 2015.
The diterpene (1R,3E,7E,11S,12S)-3,7,18-dolabellatriene from the marine brown alga Dilophus spiralis belongs to the dolabellanes natural product family and has antimicrobial activity against multi-drug resistant Staphylococcus aureus. Recently, we generated a CotB2 diterpene synthase mutant (W288G), which instead of its native product cyclooctat-9-en-7-ol, generates (1R,3E,7E,11S,12S)-3,7,18-dolabellatriene. In vivo CotB2 W288G reconstitution in an Escherichia coli based terpene production system, allowed efficient production of this olefinic macrocycle. To diversify the 3,7,18-dolabellatriene bioactivity we evaluated chemical and enzymatic methods for selective oxidation. Epoxidation by acetic peracid, which was formed in situ by a lipase catalyzed reaction of acetic acid with H2O2, provided efficient access to two monooxidized dolabellanes and to a novel di-epoxidated dolabellane species. These compounds could act as synthons en-route to new dolabellanes with diversified bioactivities. Furthermore, we demonstrate the almost quantitative 3,7,18-dolabellatriene conversion into the new, non-natural compound (1R,3E,7E,11S,12S,18R)-dolabella-3,7-diene-20-ol by hydroboration-oxidation with an enantiomeric excess of 94%, for the first time.
来自海洋褐藻螺旋双歧藻的二萜（1R,3E,7E,11S,12S）-3,7,18-多拉贝拉三烯属于多拉贝拉烷类天然产物家族，对耐多药金黄色葡萄球菌具有抗菌活性。最近，我们构建了一种CotB2二萜合酶突变体（W288G），该突变体产生的不是其天然产物环辛-9-烯-7-醇，而是（1R,3E,7E,11S,12S）-3,7,18-多拉贝拉三烯。在基于大肠杆菌的萜类化合物生产系统中对CotB2 W288G进行体内重组，能够高效生产这种烯烃大环化合物。为了使3,7,18-多拉贝拉三烯的生物活性多样化，我们评估了选择性氧化的化学和酶促方法。通过脂肪酶催化乙酸与过氧化氢原位反应形成的过氧乙酸进行环氧化反应，能够高效合成两种单氧化的多拉贝拉烷类化合物以及一种新型的双环氧化多拉贝拉烷类化合物。这些化合物可作为合成中间体，用于合成具有多样化生物活性的新型多拉贝拉烷类化合物。此外，我们首次通过硼氢化氧化反应，以94%的对映体过量将3,7,18-多拉贝拉三烯几乎定量地转化为新的非天然化合物（1R,3E,7E,11S,12S,18R）-多拉贝拉-3,7-二烯-20-醇。
