Improving heterologous polyketide production in Escherichia coli by overexpression of an S-adenosylmethionine synthetase gene
Improving heterologous polyketide production in Escherichia coli by overexpression of an S-adenosylmethionine synthetase gene
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DOI：
10.1007/s00253-007-1172-9
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发表时间：
2007-11-01
影响因子：
5
通讯作者：
Pfeifer, Blaine A.
中科院分区：
文献类型：
--
作者：
Wang, Yong;Boghigian, Brett A.;Pfeifer, Blaine A.
从Streptomyces spectabilis中克隆出一个s -腺苷蛋氨酸合成酶基因（metK），在诱导型T7启动子的控制下克隆到表达质粒中，并导入大肠杆菌BAP1(pBP130/pBP144)，该菌株能产生6-脱氧赤素内酯B （6-dEB）。mek在BAP1（pBP130/pBP144）中的共表达使6-dEB的特异性产量从10.86 mg l(-1) OD -1600提高到20.08 mg l(-1) OD -1600。为了探究这种改善的原因，我们基于mek代谢途径进行了一系列基因缺失和表达实验，该途径在丙酰辅酶a （6-dEB前体）和自诱导剂化合物之间分支。缺失和表达研究表明，自诱导剂途径对改善6-dEB的生物合成有较大影响。支持这些结果的实验表明，条件介质（自动诱导化合物的可疑位置）对6-dEB的产生有积极影响。综上所述，本研究结果表明，外源6-dEB产生的增加伴随着外源metK基因表达的增加，并表明这种改善的机制与天然自诱导剂化合物有关。
An S-adenosylmethionine synthetase gene (metK) from Streptomyces spectabilis was cloned into an expression plasmid under the control of an inducible T7 promoter and introduced into a strain of Escherichia coli (BAP1(pBP130/pBP144)) capable of producing the polyketide product 6-deoxyerythronolide B (6-dEB). The metK coexpression in BAP1(pBP130/pBP144) improved the specific production of 6-dEB from 10.86 to 20.08 mg l(-1) OD -1600. In an effort to probe the reason for this improvement, a series of gene deletion and expression experiments were conducted based on a metK metabolic pathway that branches between propionyl-CoA a 6-dEB precursor) and autoinducer compounds. The deletion and expression studies suggested that the autoinducer pathway had a larger impact on improved 6-dEB biosynthesis. Supporting these results were experiments demonstrating the positive effect conditioned media ( the suspected location of the autoinducer compounds) had on 6-dEB production. Taken together, the results of this study show an increase in heterologous 6-dEB production concomitant with heterologous metK gene expression and suggest that the mechanism for this improvement is linked to native autoinducer compounds.