FaQR, required for the biosynthesis of the strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone, encodes an enone oxidoreductase
FaQR, required for the biosynthesis of the strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone, encodes an enone oxidoreductase
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DOI：
10.1105/tpc.105.039784
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发表时间：
2006-04-01
期刊：
影响因子：
11.6
通讯作者：
Muñoz-Blanco, J
中科院分区：
文献类型：
--
作者：
Raab, T;López-Ráez, JA;Muñoz-Blanco, J
草莓（Fragaria x ananassa）果实的风味主要由一组不常见的具有2,5-二甲基-3(H)-呋喃酮结构的香气化合物组成。我们报道了一种参与4-羟基-2,5-二甲基-3(2H)-呋喃酮（HDMF；呋喃醇）生物合成的酶的表征，呋喃醇是草莓中关键的风味化合物。蛋白质提取物部分纯化，观察到酶活性的分布与存在一个类似37 kD的单一多肽相关。序列分析显示，这两个肽片段与一种强成熟诱导的生长素依赖性醌氧化还原酶FaQR （Fragaria x ananassa醌氧化还原酶）的蛋白序列完全一致。FaQR cDNA的开放阅读框由969 bp组成，编码322个氨基酸的蛋白，计算分子质量为34.3 kD。激光捕获显微解剖，然后进行RNA提取和扩增，证实在草莓果实薄壁组织中存在FaQR mRNA。FaQR蛋白在大肠杆菌中功能表达，该单体催化HDMF的形成。经化学合成和液相色谱-串联质谱分析，证实4-羟基-5-甲基-2-亚甲基-3(2H)-呋喃酮是FaQR的底物和HDMF的天然前体。本研究证实了FaQR酶作为烯酮氧化还原酶在HDMF生物合成中的作用，为草莓风味的改良和HDMF的生物技术生产提供了基础。
The flavor of strawberry (Fragaria x ananassa) fruit is dominated by an uncommon group of aroma compounds with a 2,5-dimethyl-3(H)-furanone structure. We report the characterization of an enzyme involved in the biosynthesis of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol), the key flavor compound in strawberries. Protein extracts were partially purified, and the observed distribution of enzymatic activity correlated with the presence of a single polypeptide of similar to 37 kD. Sequence analysis of two peptide fragments showed total identity with the protein sequence of a strongly ripening-induced, auxin-dependent putative quinone oxidoreductase, Fragaria x ananassa quinone oxidoreductase (FaQR). The open reading frame of the FaQR cDNA consists of 969 bp encoding a 322-amino acid protein with a calculated molecular mass of 34.3 kD. Laser capture microdissection followed by RNA extraction and amplification demonstrated the presence of FaQR mRNA in parenchyma tissue of the strawberry fruit. The FaQR protein was functionally expressed in Escherichia coli, and the monomer catalyzed the formation of HDMF. After chemical synthesis and liquid chromatography-tandem mass spectrometry analysis, 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone was confirmed as a substrate of FaQR and the natural precursor of HDMF. This study demonstrates the function of the FaQR enzyme in the biosynthesis of HDMF as enone oxidoreductase and provides a foundation for the improvement of strawberry flavor and the biotechnological production of HDMF.