A Novel Glucosylation Reaction on Anthocyanins Catalyzed by Acyl-Glucose-Dependent Glucosyltransferase in the Petals of Carnation and Delphinium
A Novel Glucosylation Reaction on Anthocyanins Catalyzed by Acyl-Glucose-Dependent Glucosyltransferase in the Petals of Carnation and Delphinium
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DOI：
10.1105/tpc.110.077487
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发表时间：
2010-10-01
期刊：
影响因子：
11.6
通讯作者：
Ozeki, Yoshihiro
中科院分区：
文献类型：
--
作者：
Matsuba, Yuki;Sasaki, Nobuhiro;Ozeki, Yoshihiro
康乃馨（香石竹）和飞燕草（飞燕草）中花青素苷的葡萄糖基化涉及新型糖供体，芳香酰基葡萄糖，在由酰基葡萄糖依赖性花青素苷5（7）-O-葡萄糖基转移酶（AA 5 GT和AA 7 GT）催化的反应中。从香石竹花瓣中纯化AA 5 GT酶，并分离编码香石竹Dc AA 5 GT和飞燕草同源物Dg AA 7 GT的cDNA。重组Dc AA 5GT和Dg AA 7 GT蛋白在体外具有AA 5GT和AA 7 GT活性。虽然Dc AA 5GT在发育中的香石竹花瓣中的表达在早期最高，但AA 5GT活性和花青素积累在后期继续增加。无论是Dc AA 5GT的表达，也没有观察到AA 5GT活性突变康乃馨的花瓣，这些花瓣积累花青素缺乏葡萄糖基部分在5位。突变体康乃馨花瓣细胞中Dc AA 5GT的瞬时表达预期导致葡萄糖部分转移到花青素苷的5位。Dc AA 5 GT和Dg AA 7 GT的氨基酸序列与通常充当β-糖苷酶的糖苷水解酶家族1蛋白高度相似。氨基酸序列的系统发育分析表明，其他植物物种可能有类似的酰基葡萄糖依赖性葡萄糖基转移酶。
Glucosylation of anthocyanin in carnations (Dianthus caryophyllus) and delphiniums (Delphinium grandiflorum) involves novel sugar donors, aromatic acyl-glucoses, in a reaction catalyzed by the enzymes acyl-glucose-dependent anthocyanin 5 (7)-O-glucosyltransferase (AA5GT and AA7GT). The AA5GT enzyme was purified from carnation petals, and cDNAs encoding carnation Dc AA5GT and the delphinium homolog Dg AA7GT were isolated. Recombinant Dc AA5GT and Dg AA7GT proteins showed AA5GT and AA7GT activities in vitro. Although expression of Dc AA5GT in developing carnation petals was highest at early stages, AA5GT activity and anthocyanin accumulation continued to increase during later stages. Neither Dc AA5GT expression nor AA5GT activity was observed in the petals of mutant carnations; these petals accumulated anthocyanin lacking the glucosyl moiety at the 5 position. Transient expression of Dc AA5GT in petal cells of mutant carnations is expected to result in the transfer of a glucose moiety to the 5 position of anthocyanin. The amino acid sequences of Dc AA5GT and Dg AA7GT showed high similarity to glycoside hydrolase family 1 proteins, which typically act as beta-glycosidases. A phylogenetic analysis of the amino acid sequences suggested that other plant species are likely to have similar acyl-glucose-dependent glucosyltransferases.