X-ray crystal structure of human dopamine sulfotransferase, SULT1A3 - Molecular modeling and quantitative structure-activity relationship analysis demonstrate a molecular basis for sulfotransferase substrate specificity
X-ray crystal structure of human dopamine sulfotransferase, SULT1A3 - Molecular modeling and quantitative structure-activity relationship analysis demonstrate a molecular basis for sulfotransferase substrate specificity
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DOI：
10.1074/jbc.274.53.37862
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发表时间：
1999-12-31
影响因子：
4.8
通讯作者：
Coughtrie, MWH
中科院分区：
文献类型：
--
作者：
Dajani, R;Cleasby, A;Coughtrie, MWH
人类是少数几个产生大量硫酸儿茶酚胺的物种之一，他们已经进化出一种特异性的磺基转移酶SULT 1A 3（M-PST），以催化这些缀合物的形成。在其他物种中还没有发现一种正磷酸酶蛋白。为了进一步了解这种酶独特底物选择性的分子基础，我们已经在2.5埃分辨率下解析了与3 '-磷酸腺苷5'-磷酸（PAP）复合的人SULT 1A 3的晶体结构，并对一系列酚和儿茶酚进行了定量结构活性关系（QSAR）分析。SULT 1A 3采用与小鼠雌激素磺基转移酶类似的折叠，具有被α-螺旋包围的中央五链β-折叠。SULT 1A 3在溶液中是二聚体，但在细胞的不对称单元中与单体结晶，尽管二聚体界面是通过跨结晶学2-折叠轴的相互作用形成的。定量构效关系分析表明，该酶是高度选择性的儿茶酚，特别是儿茶酚胺，和氢键基团和亲脂性（cLogD）强烈影响K-m。我们还使用定点诱变进一步研究了Glu（146）在SULT 1A 3中的作用，并表明它不仅在定义多巴胺的选择性方面，而且在阻止许多酚类外源性物质与酶结合方面起着关键作用。
Humans are one of the few species that produce large amounts of catecholamine sulfates, and they have evolved a specific sulfotransferase, SULT1A3 (M-PST), to catalyze the formation of these conjugates. An orthologous protein has yet to be found in other species. To further our understanding of the molecular basis for the unique substrate selectivity of this enzyme, we have solved the crystal structure of human SULT1A3, complexed with 3'-phosphoadenosine 5'-phosphate (PAP), at 2.5 Angstrom resolution and carried out quantitative structure-activity relationship (QSAR) analysis with a series of phenols and catechols. SULT1A3 adopts a similar fold to mouse estrogen sulfotransferase, with a central five-stranded beta-sheet surrounded by alpha-helices. SULT1A3 is a dimer in solution but crystallized with a monomer in the asymmetric unit of the cell, although dimer interfaces were formed by interaction across crystallographic 2-fold axes. QSAR analysis revealed that the enzyme is highly selective for catechols, and catecholamines in particular, and that hydrogen bonding groups and lipophilicity (cLogD) strongly influenced K-m. We also investigated further the role of Glu(146) in SULT1A3 using site-directed mutagenesis and showed that it plays a key role not only in defining selectivity for dopamine but also in preventing many phenolic xenobiotics fi om binding to the enzyme.