Formation of a complex pattern of sinapate esters in Brassica napus seeds, catalyzed by enzymes of a serine carboxypeptidase-like acyltransferase family?
Formation of a complex pattern of sinapate esters in Brassica napus seeds, catalyzed by enzymes of a serine carboxypeptidase-like acyltransferase family?
复制标题
DOI：
10.1016/j.phytochem.2005.02.031
复制
发表时间：
2005-06-01
期刊：
影响因子：
3.8
通讯作者：
Strack, D
中科院分区：
文献类型：
--
作者：
Baumert, A;Milkowski, C;Strack, D
十字花科植物积累了复杂模式的芥子酸酯，正如与油菜（Brassica napus）种子的交流所显示的那样。通过高场核磁共振波谱和高分辨率电喷雾电离质谱的结合分离和鉴定了 15 种种子成分。其中包括葡萄糖、龙胆二糖和山奈酚糖苷酯以及芥子碱（芥子酰胆碱）、芥子酰苹果酸酯和不寻常的环状亚精胺酰胺。一种葡萄糖酯（1,6-二-O-芥子酰葡萄糖）、两种龙胆二糖酯（1-O-咖啡酰龙胆二糖和1,2,6'-三-O-芥子酰龙胆二糖）和两种山奈酚缀合物[4'-(6-O-芥子酰葡萄糖苷)-3,7-二-O-葡萄糖苷和3-O-槐糖苷-7-O-(2-O-芥子酰葡萄糖苷)]似乎是新的植物产品。丝氨酸羧肽酶样 (SCPL) 酰基转移酶催化芥子碱和芥子酰苹果酸的形成，接受 1-O-β-缩醛酯（1-O-β-葡萄糖酯）作为酰基供体。为了解决甘蓝型油菜种子中芥子酸酯复杂模式的其他成分的形成是否是通过 1-O-芥子酰-β-葡萄糖催化的问题，我们对芥子酸葡萄糖基转移酶基因 (BnSGT1) 表达进行了基于种子特异性 dsRNAi 的抑制。在 BnSGT1 抑制植物的种子中，芥子酰葡萄糖的量降低到 HPLC 检测限以下，从而导致所有其他芥子酸酯消失或显着减少，表明甘蓝型油菜种子中这些酯的复杂模式的形成依赖于芥子酰葡萄糖。这就产生了这样的假设：SCPL 酰基转移酶家族的酶催化适当的转移反应以合成累积的酯。 (c) 2005 Elsevier Ltd. 保留所有权利。
Members of the Brassicaceae accumulate complex patterns of sinapate esters, as shown in this communication with seeds of oil-seed rape (Brassica napus). Fifteen seed constituents were isolated and identified by a combination of high-field NMR spectroscopy and high resolution electrospray ionisation mass spectrometry. These include glucose, gentiobiose and kaempferol glycoside esters as well as sinapine (sinapoylcholine), sinapoylmalate and an unusual cyclic spermidine amide. One of the glucose esters (1,6-di-O-sinapoylglucose), two gentiobiose esters (1-O-caffeoylgentiobiose and 1,2,6'-tri-O-sinapoylgentiobiose) and two kaempferol conjugates [4'-(6-O-sinapoylglucoside)-3,7-di-O-glucoside and 3-O-sophoroside-7-O-(2-O-sinapoylglucoside)] seem to be new plant products. Serine carboxypeptidase-like (SCPL) acyltransferases catalyze the formation of sinapine and sinapoylmalate accepting 1-O-beta-acetal esters (1-O-beta-glucose esters) as acyl donors. To address the question whether the formation of other components of the complex pattern of the sinapate esters in B. napus seeds is catalyzed via 1-O-sinapoyl-beta-glucose, we performed a seed-specific dsRNAi-based suppression of the sinapate glucosyltransferase gene (BnSGT1) expression. In seeds of BnSGT1-suppressing plants the amount of sinapoylglucose decreased below the HPLC detection limit resulting in turn in the disappearance or marked decrease of all the other sinapate esters, indicating that formation of the complex pattern of these esters in B. napus seeds is dependent on sinapoylglucose. This gives rise to the assumption that enzymes of an SCPL acyltransferase family catalyze the appropriate transfer reactions to synthesize the accumulating esters. (c) 2005 Elsevier Ltd. All rights reserved.