Cholesterol Interaction with the Trimeric HIV Fusion Protein gp41 in Lipid Bilayers Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations.
Cholesterol Interaction with the Trimeric HIV Fusion Protein gp41 in Lipid Bilayers Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations.
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DOI：
10.1016/j.jmb.2020.06.017
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发表时间：
2020-07-24
影响因子：
5.6
通讯作者：
Hong M
中科院分区：
文献类型：
--
作者：
Kwon B;Mandal T;Elkins MR;Oh Y;Cui Q;Hong M
HIV-1进入细胞由融合蛋白gp 41介导。胆固醇在这种病毒-细胞融合中起着重要的作用，但是关于胆固醇-gp 41相互作用的分子结构信息至今还不存在。在这里，我们提供了有关脂质双层中胆固醇与GP 41复合的实验和计算数据。我们专注于蛋白质的C-末端区域，其包括膜近端外部区域（MPER）和跨膜结构域（TMD）。我们测量肽胆固醇接触病毒模拟脂质双层使用固态NMR光谱，并增强这些实验数据与全原子分子动力学模拟。2D 19 F NMR谱显示MPER残基和胆固醇异辛基尾之间的相关峰，表明胆固醇与MPER-TMD三聚体分子接触。肽和13 C标记的胆固醇之间的19 F-13 C距离测量显示D环上的C17和B和C环交叉处的C9距F673侧链4- 19 F为7.0 nm。在膜中的高肽浓度下，19 F-13 C距离数据表明每个三聚体中有三个胆固醇分子结合在F673附近。胆固醇识别氨基酸共有序列（CRAC）基序的突变没有改变这些距离，表明胆固醇结合不需要这个序列基序。分子动力学模拟进一步确定了胆固醇相互作用的两个热点。总之，这些实验数据和模拟表明，螺旋-转角-螺旋构象的MPER-TMD是负责螯合胆固醇。我们建议，这种gp 41-胆固醇相互作用介导的病毒-细胞融合招募gp 41的液体无序和液体有序相的边界，引起膜曲率。
HIV-1 entry into cells is mediated by the fusion protein gp41. Cholesterol plays an important role in this virus-cell fusion, but molecular structural information about cholesterol-gp41 interaction is so far absent. Here, we present experimental and computational data about cholesterol complexation with gp41 in lipid bilayers. We focus on the C-terminal region of the protein, which comprises a membrane-proximal external region (MPER) and the transmembrane domain (TMD). We measured peptide-cholesterol contacts in virus-mimetic lipid bilayers using solid-state NMR spectroscopy, and augmented these experimental data with all-atom molecular dynamics simulations. 2D 19F NMR spectra show correlation peaks between MPER residues and the cholesterol isooctyl tail, indicating that cholesterol is in molecular contact with the MPER-TMD trimer. 19F-13C distance measurements between the peptide and 13C-labeled cholesterol show that C17 on the D ring and C9 at the intersection of B and C rings are 7.0 Å from the F673 sidechain 4-19F. At high peptide concentrations in the membrane, the 19F-13C distance data indicate three cholesterol molecules bound near F673 in each trimer. Mutation of a cholesterol-recognition amino acid consensus (CRAC) motif did not change these distances, indicating that cholesterol binding does not require this sequence motif. Molecular dynamics simulations further identify two hotspots for cholesterol interactions. Taken together, these experimental data and simulations indicate that the helix-turn-helix conformation of the MPER-TMD is responsible for sequestering cholesterol. We propose that this gp41-cholesterol interaction mediates virus-cell fusion by recruiting gp41 to the boundary of the liquid-disordered and liquid-ordered phases to incur membrane curvature.
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