The binding site of bisphenol A to protein disulphide isomerase
The binding site of bisphenol A to protein disulphide isomerase
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DOI：
10.1093/jb/mvr122
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发表时间：
2012-01-01
影响因子：
2.7
通讯作者：
Imaoka, Susumu
中科院分区：
文献类型：
--
作者：
Hashimoto, Shoko;Shiomoto, Keiko;Imaoka, Susumu
蛋白质二硫化物异构酶（PDI）已被分离作为双酚A（BPA）在大鼠脑中的结合蛋白。在这项研究中，我们确定了BPA的结合位点的PDI和特征的结合位点。首先，我们通过表面等离子体共振光谱鉴定了PDI的ab，b 'a'c，a，B，B'和a' c片段肽的BPA结合结构域。BPA与ab、b 'a'c、a和b '相互作用，表明a和B'结构域在它们的相互作用中是重要的。第二，ab、b 'a'c、a、B、b '、a'、abb 'a'、abb '、b' a '、δ B'和a 'c片段肽被用于它们与RNA酶作为底物的异构酶活性。BPA能抑制b '等肽段的催化活性，提示B'结构域参与了BPA对PDI催化活性的抑制作用。接下来，我们通过氨基酸取代研究了PDI的BPA结合能力。H258突变使PDI失去了BPA结合活性，Q245和N300突变也使其活性降低。此外，酸性条件下提高了PDI的BPA结合活性。这些结果表明，这些氨基酸的电荷，特别是H258，对于BPA与PDI结合是重要的。
Protein disulphide isomerase (PDI) has been isolated as a binding protein of bisphenol A (BPA) in the rat brain. In this study, we determined binding sites of BPA to PDI and characterized the binding site. First, we identified the BPA-binding domain with ab, b'a'c, a, b, b' and a'c fragment peptides of PDI by surface plasmon resonance spectroscopy. BPA interacted with ab, b'a 'c, a and b', suggesting that a and b' domains are important in their interaction. Second, ab, b'a'c, a,b,b',a', abb'a', abb', b'a', delta b' and a'c fragment peptides were used for their isomerase activity with RNase as a substrate. BPA could inhibit the activity of peptide fragments including b', suggesting that b' domain contributes to inhibition of catalytic activity of PDI by BPA. Next, we investigated the BPA-binding capacity of PDI by amino acid substitution. PDI lost the BPA-binding activity by the mutation of H258 and mutation of Q245 and N300 also decreased its activity. Furthermore, acidic condition increased the BPA-binding activity of PDI. These results suggest that the charge of these amino acid especially, H258, is important for the BPA to bind to PDI.