Ordered opening of LDL receptor binding domain of human apolipoprotein E3 revealed by hydrogen/deuterium exchange mass spectrometry and fluorescence spectroscopy.
Ordered opening of LDL receptor binding domain of human apolipoprotein E3 revealed by hydrogen/deuterium exchange mass spectrometry and fluorescence spectroscopy.
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氢/氘交换质谱和荧光光谱显示人载脂蛋白 E3 的 LDL 受体结合域有序开放。
DOI：
10.1016/j.bbapap.2018.08.005
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Narayanaswami,Vasanthy
中科院分区：
文献类型：
--
作者：
Yang,Liping;Hernandez,RoyV;Tran,TuyenN;Nirudodhi,Sasidhar;Beck,WendyHJ;Maier,ClaudiaS;Narayanaswami,Vasanthy
载脂蛋白E3 （apoE3）是一种可交换的载脂蛋白，在胆固醇稳态中起关键作用。apoE3的n端（NT）结构域（残基1 - 191）被折叠成一个由4个两亲性α-螺旋组成的螺旋束：H1、H2、H3和H4，在螺旋束的n端和c端分别被柔性螺旋N1和N2和铰链螺旋1（铰链H1）所包围。NT结构域在与低密度脂蛋白受体（LDLR）结合中起关键作用，最终导致血浆胆固醇水平降低。为了被LDLR识别，螺旋束必须打开并经历构象变化。本研究的目的是了解螺旋束打开的机制。氢/氘交换质谱（HDX-MS）显示，apoE3 NT结构域具有多个无序和未折叠的区域，与H1、H3和H4相比，H2对交换入的保护作用相对较小。位点定向荧光标记表明，H2不仅具有最高的溶剂暴露程度，而且在螺旋束中具有最大的柔韧性。这也表明H1的脂蛋白行为与H2、H3和H4有显著差异。这些结果表明，螺旋束的打开可能始于H2的柔性端和连接H2/H3的环，并涉及H2/H3远离H1/H4的运动。总之，这些观察结果提供了机制上的见解，表明apoE3 NT结构域的调节螺旋束开放可以由脂质结合触发。
Apolipoprotein E3 (apoE3) is an exchangeable apolipoprotein that plays a critical role in cholesterol homeostasis. The N-terminal (NT) domain of apoE3 (residues 1–191) is folded into a helix bundle comprised of 4 amphipathic α-helices: H1, H2, H3 and H4, flanked by flexible helices N1 and N2, and Hinge Helix 1 (Hinge H1), at the N-and C-terminal sides of the helix bundle, respectively. The NT domain plays a critical role in binding to the low density lipoprotein receptor (LDLR), which eventually leads to lowering of plasma cholesterol levels. In order to be recognized by the LDLR, the helix bundle has to open and undergo a conformational change. The objective of the study was to understand the mechanism of opening of the helix bundle. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) revealed that apoE3 NT domain adopts several disordered and unfolded regions, with H2 exhibiting relatively little protection against exchange-in compared to H1, H3, and H4. Site-directed fluorescence labeling indicated that H2 not only has the highest degree of solvent exposure but also the most flexibility in the helix bundle. It also indicated that the lipoprotein behavior of H1 was significnatly different from that of H2, H3 and H4. These results suggest that the opening of the helix bundle is likely initiated at the flexible end of H2 and the loop linking H2/H3, and involves movement of H2/H3 away from H1/H4. Together, these observations offer mechanistic insight suggesting a regulated helix bundle opening of apoE3 NT domain can be triggered by lipid binding.
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DOI：
10.1016/j.bbapap.2014.06.007
发表时间：
2014-09
影响因子：
3.2
作者：
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影响因子：
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DOI：
--
发表时间：
2009
期刊：
European Biophysics Journal
影响因子：
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影响因子：
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作者：
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