Structural basis for non-genuine phenolic acceptor substrate specificity of Streptomyces roseochromogenes prenyltransferase CloQ from the ABBA/PT-barrel superfamily.
Structural basis for non-genuine phenolic acceptor substrate specificity of Streptomyces roseochromogenes prenyltransferase CloQ from the ABBA/PT-barrel superfamily.
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DOI：
10.1371/journal.pone.0174665
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Vincken JP
中科院分区：
文献类型：
--
作者：
Araya-Cloutier C;Martens B;Schaftenaar G;Leipoldt F;Gruppen H;Vincken JP
受体底物特异性的链霉菌roseochromogenes异戊烯基转移酶SrCloQ进行了研究，使用不同的非真正的酚类化合物。RP-UHPLC-UV-MSn用于异戊二烯化产物的初步注释和定量。具有不同类型取代的黄酮类化合物、异黄酮类化合物和芪类化合物被SrCloQ异戊烯化，尽管其效率低于真正的底物4-羟基苯丙酮酸。异黄烷雌马酚，其次是黄酮7，4 '-二羟基黄酮，是最好的非真正受体底物。B-环C-异戊烯化通常优于A-环C-异戊烯化（比率5：1）。B环朝向供体底物二甲基烯丙基焦磷酸的非真正受体底物的对接研究表明，C环的羰基能够与残基Arg 160产生稳定的相互作用，这可能决定了观察到的B环异戊烯化的偏好。当受体底物没有酚羟基时，没有形成反应产物。这种偏好可以通过酚羟基和残基Glu 281之间所需的必要氢键来解释。在C3'位置（B-环）具有额外羟基的受体底物主要是O3'-异戊二烯化的（> 80%的反应产物）。这可以通过C3'羟基在催化位点处接近供体底物来解释。SrCloQ对黄酮类化合物的选择优于对异黄酮类化合物。对接的研究表明，B-环和酚羟基基团的位置C7（A-环）的黄酮对残基Tyr 233的方向在这一观察到的偏好起着重要的作用。最后，对SrCloQ的受体底物特异性和区域选择性获得的见解扩展到来自CloQ/NhpB家族的其他异戊二烯基转移酶。
Acceptor substrate specificity of Streptomyces roseochromogenes prenyltransferase SrCloQ was investigated using different non-genuine phenolic compounds. RP-UHPLC-UV-MSn was used for the tentative annotation and quantification of the prenylated products. Flavonoids, isoflavonoids and stilbenoids with different types of substitution were prenylated by SrCloQ, although with less efficiency than the genuine substrate 4-hydroxyphenylpyruvate. The isoflavan equol, followed by the flavone 7,4’-dihydroxyflavone, were the best non-genuine acceptor substrates. B-ring C-prenylation was in general preferred over A-ring C-prenylation (ratio 5:1). Docking studies of non-genuine acceptor substrates with the B-ring oriented towards the donor substrate dimethylallyl pyrophosphate, showed that the carbonyl group of the C-ring was able to make stabilizing interactions with the residue Arg160, which might determine the preference observed for B-ring prenylation. No reaction products were formed when the acceptor substrate had no phenolic hydroxyl groups. This preference can be explained by the essential hydrogen bond needed between a phenolic hydroxyl group and the residue Glu281. Acceptor substrates with an additional hydroxyl group at the C3’ position (B-ring), were mainly O3’-prenylated (> 80% of the reaction products). This can be explained by the proximity of the C3’ hydroxyl group to the donor substrate at the catalytic site. Flavones were preferred over isoflavones by SrCloQ. Docking studies suggested that the orientation of the B-ring and of the phenolic hydroxyl group at position C7 (A-ring) of flavones towards the residue Tyr233 plays an important role in this observed preference. Finally, the insights obtained on acceptor substrate specificity and regioselectivity for SrCloQ were extended to other prenyltransferases from the CloQ/NhpB family.