The Interplay between a Multifunctional Dehydratase Domain and a C-Methyltransferase Effects Olefin Shift in Ambruticin Biosynthesis
The Interplay between a Multifunctional Dehydratase Domain and a C-Methyltransferase Effects Olefin Shift in Ambruticin Biosynthesis
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DOI：
10.1002/anie.201607827
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发表时间：
2016-10-17
影响因子：
16.6
通讯作者：
Hahn, Frank
中科院分区：
文献类型：
--
作者：
Berkhan, Gesche;Merten, Christian;Hahn, Frank
烯烃转移是聚酮生物合成过程中一个重要的改性过程。特别是对于i型cis-AT PKS，很少有关于所涉及的酶机制的信息。我们提出了我们的体外研究烯烃转移发生在阿姆霉素生物合成过程中。独特的多功能结构域AmbDH4催化连续脱水、外映异构和烯基异构化。由高度特异性的c -甲基转移酶AmbM催化的-甲基化作用使3-乙烯酸酯脱离平衡。这种热力学上不利的整体过程是由所涉及的酶的高一致的底物特异性实现的。AmbDH4与DH结构域有密切的关系，初步的机制研究表明，烯烃的转移是通过类似的质子穿梭机制发生的，就像之前描述的反式at - pks的EI结构域一样。
The olefin shift is an important modification during polyketide biosynthesis. Particularly for typeI cis-AT PKS, little information has been gained on the enzymatic mechanisms involved. We present our invitro investigations on the olefin shift occurring during ambruticin biosynthesis. The unique, multifunctional domain AmbDH4 catalyzes consecutive dehydration, epimerization, and enoyl isomerization. The resulting 3-enethioate is removed from the equilibrium by -methylation catalyzed by the highly specific C-methyltransferase AmbM. This thermodynamically unfavorable overall process is enabled by the high, concerted substrate specificity of the involved enzymes. AmbDH4 shows close relationship to DH domains and initial mechanistic studies suggest that the olefin shift occurs via a similar proton-shuttling mechanism as previously described for EI domains from trans-AT-PKS.