Structural and mutational studies of anthocyanin malonyltransferases establish the features of BAHD enzyme catalysis
Structural and mutational studies of anthocyanin malonyltransferases establish the features of BAHD enzyme catalysis
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DOI：
10.1074/jbc.m700638200
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发表时间：
2007-05-25
影响因子：
4.8
通讯作者：
Nakayama, Toru
中科院分区：
文献类型：
--
作者：
Unno, Hideaki;Ichimaida, Fumiko;Nakayama, Toru
BAHD家族是一类酰基辅酶a依赖性酰基转移酶，参与植物次生代谢，并对酰基受体表现出多种特异性。花青素酰基转移酶是BAHD家族中重要的一类，它能催化花青素的酰基化，而花青素是大多数花从红到蓝的主要原因。在这里，我们描述了从红菊花花瓣中提取的三种类似的花青素丙二醇转移酶的晶体学和突变研究：花青素30 - o -葡萄糖苷-6 '- o -丙二醇转移酶（Dm3MaT1），花青素3- o -葡萄糖苷-3 ',6 '- o -二丙二醇转移酶（Dm3MaT2）和同源物（Dm3MaT3）。突变分析显示，在Dm3MaT1和Dm3MaT2之间，N端和c端区域的7个氨基酸残基对差异酰基受体特异性很重要。Dm3MaT3的晶体学研究提供了BAHD成员与酰基辅酶a络合的第一个结构，显示了酶与酰基辅酶a分子之间的详细相互作用。该结构结合突变分析结果，使我们能够确定花青素丙二醇转移酶的酰基受体结合位点，该位点在结构上不同于另一BAHD成员vinorine synthase的相应部分，从而使我们能够了解BAHD家族酰基受体特异性的多样性。
The BAHD family is a class of acyl-CoA-dependent acyltransferases that are involved in plant secondary metabolism and show a diverse range of specificities for acyl acceptors. Anthocyanin acyltransferases make up an important class of the BAHD family and catalyze the acylation of anthocyanins that are responsible for most of the red-to-blue colors of flowers. Here, we describe crystallographic and mutational studies of three similar anthocyanin malonyltransferases from red chrysanthemum petals: anthocyanidin 3O-glucoside-6 ''-O-malonyltransferase ( Dm3MaT1), anthocyanidin 3-O-glucoside-3 '', 6 ''-O-dimalonyltransferase (Dm3MaT2), and a homolog ( Dm3MaT3). Mutational analyses revealed that seven amino acid residues in the N- and C-terminal regions are important for the differential acyl-acceptor specificity between Dm3MaT1 and Dm3MaT2. Crystallographic studies of Dm3MaT3 provided the first structure of a BAHD member, complexed with acyl-CoA, showing the detailed interactions between the enzyme and acyl-CoA molecules. The structure, combined with the results of mutational analyses, allowed us to identify the acyl-acceptor binding site of anthocyanin malonyltransferases, which is structurally different from the corresponding portion of vinorine synthase, another BAHD member, thus permitting the diversity of the acyl-acceptor specificity of BAHD family to be understood.