Structure-function modeling of the interactions of N-alkyl-N-hydroxyanilines with rat hepatic aryl sulfotransferase IV.
Structure-function modeling of the interactions of N-alkyl-N-hydroxyanilines with rat hepatic aryl sulfotransferase IV.
复制标题
N-烷基-N-羟基苯胺与大鼠肝芳基磺基转移酶 IV 相互作用的结构-功能模型。
DOI：
10.1021/tx990184z
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发表时间：
2000
影响因子：
4.1
通讯作者：
Duffel,MW
中科院分区：
文献类型：
--
作者：
King,RS;Sharma,V;Pedersen,LC;Kakuta,Y;Negishi,M;Duffel,MW
虽然以前的研究已经清楚地表明N-羟基芳胺和N-羟基杂环胺是磺基转移酶的底物，但对于当时的羟基芳胺的哪些结构特征对硫酸盐化起重要作用还知之甚少。这项研究的目的是确定N-烷基-N-羟基芳胺与芳基磺基转移酶(AST)IV(也称为酪氨酸酯磺基转移酶或ST1A1)的相互作用程度，并使用分子模拟技术评估这些相互作用。AST IV是大鼠体内一种主要的胞浆磺基转移酶，它催化多种酚、苯甲醇、芳基异羟肟酸、肟类和伯羟基芳胺的硫化反应。在本研究中，N-羟基-N-甲基苯胺、N-乙基-N-羟基苯胺和N-羟基-N-正丙基苯胺是纯化的大鼠肝脏AST IV的底物。然而，当当时的烷基取代基为正丁基(即N-正丁基-N-羟基苯胺)时，与酶的相互作用从底物的作用转变为竞争抑制。通过构建和使用基于小鼠雌激素磺基转移酶的AST IV模型，进一步探索了这种特异性的变化，该酶的晶体结构已被确定为高分辨率。分子建模技术被用来将每个芳香胺对接到AST IV的同源模型的活性位置上，并确定最佳的配体几何构型。这些实验结果表明，在AST IV的活性部位上，对次级N-烷基-N-羟基芳胺结合方向的空间限制在决定酶与这些化合物相互作用的性质方面起着重要的作用。
Although previous investigations have clearly shown thatN-hydroxy arylamines andN-hydroxy heterocyclic amines are substrates for sulfotransferases, relatively little is known about which structural features of theN-hydroxy arylamines are important for sulfation to occur. The purpose of this investigation was to determine the extent to which secondaryN-alkyl-N-hydroxy arylamines interact with aryl sulfotransferase (AST) IV (also known as tyrosine-ester sulfotransferase or ST1A1) and to evaluate these interactions using molecular modeling techniques. AST IV is a major cytosolic sulfotransferase in the rat, and it catalyzes the sulfation of various phenols, benzylic alcohols, arylhydroxamic acids, oximes, and primaryN-hydroxy arylamines. In this study, three secondaryN-hydroxy arylamines,N-hydroxy-N-methylaniline,N-ethyl-N-hydroxyaniline, andN-hydroxy-N-n-propylaniline, were found to be substrates for the purified rat hepatic AST IV. However, when theN-alkyl substituent was ann-butyl group (i.e.,N-n-butyl-N-hydroxyaniline), the interaction with the enzyme changed from that of a substrate to competitive inhibition. This change in specificity was further explored through the construction and use of a model for AST IV based on mouse estrogen sulfotransferase, an enzyme whose crystal structure has been previously determined to high resolution. Molecular modeling techniques were used to dock each of the aboveN-hydroxy arylamines into the active site of the homology model of AST IV and determine optimum ligand geometries. The results of these experiments indicated that steric constraints on the orientation of binding of secondaryN-alkyl-N-hydroxy arylamines at the active site of AST IV play a significant role in determining the nature of the interaction of the enzyme with these compounds.