Structure and epimerase activity of anthocyanidin reductase from Vitis vinifera
Structure and epimerase activity of anthocyanidin reductase from Vitis vinifera
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DOI：
10.1107/s0907444909025013
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发表时间：
2009-09-01
影响因子：
2.2
通讯作者：
Gallois, Bernard
中科院分区：
文献类型：
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作者：
Gargouri, Mahmoud;Manigand, Claude;Gallois, Bernard
花青素还原酶（anthocyanidin reductase， ANR）与白花青素还原酶（leoanocyanidin reductase， ANR）是类黄酮生物合成途径中的两种酶之一，可产生形成原花青素或缩合单宁所需的黄烷-3-醇单体。它催化花青素的二次还原生成2R，3R-黄烷-3-醇，这些黄烷-3-醇可以通过非酶外映进一步转化为2S，3R异构体。以葡萄（Vitis vinifera）为原料，在大肠杆菌中表达并纯化了ANR。出乎意料的是，RP-HPLC， LC-MS和NMR实验清楚地表明，该酶产生50:50的2,3-顺式和2,3-反式黄烷-3-醇混合物，通过手性色谱鉴定为2S，3S-和2S， 3r -黄烷-3-醇，即天然稀有的(+)-表儿茶素和(-)-儿茶素，当花青素作为反应底物时。ANR的第一个三维结构以2.2 a的分辨率描述，并解释了在高盐浓度存在下酶的不活性。
Together with leucoanthocyanidin reductase, anthocyanidin reductase (ANR) is one of the two enzymes of the flavonoid-biosynthesis pathway that produces the flavan-3-ol monomers required for the formation of proanthocyanidins or condensed tannins. It has been shown to catalyse the double reduction of anthocyanidins to form 2R,3R-flavan-3-ols, which can be further transformed to the 2S,3R isomers by non-enzymatic epimerization. ANR from grape (Vitis vinifera) was expressed in Escherichia coli and purified. Unexpectedly, RP-HPLC, LC-MS and NMR experiments clearly established that the enzyme produces a 50:50 mixture of 2,3-cis and 2,3-trans flavan-3-ols which have been identified by chiral chromatography to be 2S,3S- and 2S,3R-flavan-3-ols, i.e. the naturally rare (+)-epicatechin and (-)-catechin, when cyanidin is used as the substrate of the reaction. The first three-dimensional structure of ANR is described at a resolution of 2.2 A and explains the inactivity of the enzyme in the presence of high salt concentrations.