How Do Branched Detergents Stabilize GPCRs in Micelles?
How Do Branched Detergents Stabilize GPCRs in Micelles?
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DOI：
10.1021/acs.biochem.0c00183
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发表时间：
2020-06-16
期刊：
影响因子：
2.9
通讯作者：
Vaidehi, Nagarajan
中科院分区：
文献类型：
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作者：
Lee, Sangbae;Ghosh, Soumadwip;Vaidehi, Nagarajan
人们通常在洗涤剂胶束环境中研究G蛋白偶联受体(GPCRs)的结构和功能特性，但许多GPCRs往往在短烷基链洗涤剂中变性或聚集。在我们以前的工作中[Lee，S.，et al.(2016)J.Am化学。Soc.138,15425-15433]，我们发现烷基葡萄糖苷中的GPCRs是高度动态的，导致洗涤剂分子在跨膜α-螺旋之间穿透，这是受体变性的第一步。尽管十二烷基麦芽糖苷(DDM，也称为十二烷基麦芽糖苷)中的GPCRs没有观察到这种情况，但即使是这种洗涤剂也不够温和，不足以在提纯过程中保持许多GPCRs的完整性。十二烷基麦芽糖新戊二醇(LMNG)洗涤剂被发现在天然状态下纯化GPCRs具有显著的优势，因为它们比DDM赋予受体更多的稳定性。为了深入了解它们是如何稳定GPCRs的，我们使用原子分子动力学模拟了各种洗涤剂(LMNG、DMNG、OGNG和DDM)中的野生型腺苷A(2A)受体(WT-A(2A)R)、热稳定的A(2A)R(Ta(2A)R)和野生型β(2)-肾上腺素受体(β(2)AR)。对Ta(2A)R在LMNG、DMNG和OGNG中的分子动力学模拟分析表明，该系列洗涤剂的行为与我们先前研究中类似的系列洗涤剂DDM、DM和OG非常相似。然而，将LMNG和DDM的行为进行比较，发现两者之间存在显著差异。LMNG的运动比DDM小得多，这导致受体疏水区域周围的脂肪链密度增加，头基之间形成更多的氢键。这有助于增强洗涤剂分子之间以及受体和洗涤剂之间的相互作用能量，解释了在该洗涤剂中纯化的GPCRs稳定性增强的原因。支化洗涤剂堵塞了跨膜螺旋之间，降低了它们的弹性。我们的结果为开发稳定膜蛋白的洗涤剂变体提供了合理的基础。
The structural and functional properties of G protein-coupled receptors (GPCRs) are often studied in a detergent micellar environment, but many GPCRs tend to denature or aggregate in short alkyl chain detergents. In our previous work [Lee, S., et al. (2016) J. Am. Chem. Soc.138, 15425-15433], we showed that GPCRs in alkyl glucosides were highly dynamic, resulting in the penetration of detergent molecules between transmembrane alpha-helices, which is the initial step in receptor denaturation. Although this was not observed for GPCRs in dodecyl maltoside (DDM, also known as lauryl maltoside), even this detergent is not mild enough to preserve the integrity of many GPCRs during purification. Lauryl maltose neopentylglycol (LMNG) detergents have been found to have significant advantages for purifying GPCRs in a native state as they impart more stability to the receptor than DDM. To gain insights into how they stabilize GPCRs, we used atomistic molecular dynamics simulations of wild type adenosine A(2A) receptor (WT-A(2A)R), thermostabilized A(2A)R (tA(2A)R), and wild type beta(2)-adrenoceptor (beta(2)AR) in a variety of detergents (LMNG, DMNG, OGNG, and DDM). Analysis of molecular dynamics simulations of tA(2A)R in LMNG, DMNG, and OGNG showed that this series of detergents exhibited behavior very similar to that of an analogous series of detergents DDM, DM, and OG in our previous study. However, there was a striking difference upon comparison of the behavior of LMNG to that of DDM. LMNG showed considerably less motion than DDM, which resulted in the enhanced density of the aliphatic chains around the hydrophobic regions of the receptor and considerably more hydrogen bond formation between the head groups. This contributed to enhanced interaction energies between both detergent molecules and between the receptor and detergent, explaining the enhanced stability of GPCRs purified in this detergent. Branched detergents occlude between transmembrane helices and reduce their flexibility. Our results provide a rational foundation to develop detergent variants for stabilizing membrane proteins.