Protein-Induced Membrane Curvature Investigated through Molecular Dynamics Flexible Fitting
Protein-Induced Membrane Curvature Investigated through Molecular Dynamics Flexible Fitting
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DOI：
10.1016/j.bpj.2009.04.031
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发表时间：
2009-07-08
影响因子：
3.4
通讯作者：
Schulten, Klaus
中科院分区：
文献类型：
--
作者：
Hsin, Jen;Gumbart, James;Schulten, Klaus
在光合作用的紫色细菌中，红细菌(Rhodbacter(RBA.)球藻，光被膜结合的捕光蛋白LH1和LH2吸收。LH1直接围绕反应中心(RC)，与PufX一起形成二聚体(RC-LH1-PufX)(2)蛋白质复合体。在缺乏LH2的澳大利亚央行。球状突变体RC-LH1-PufX二聚体聚集成半径约为250-550埃的管状小泡，使RC-LH1-PufX成为为数不多的具有诱导膜弯曲活性的完整膜蛋白之一。近日，一张三维电子显微镜密度图显示，澳大利亚央行。球状球状杆菌RC-LH1-PufX二聚体在其二聚化界面上显示出明显的弯曲。为了研究这种高弯曲蛋白质的曲率特性，我们使用分子动力学模拟来拟合电子显微镜密度图中RC-LH1-PufX二聚体的全原子结构模型。模拟揭示了晚餐如何产生具有高局部曲率的膜，即使PufX的位置还不能唯一确定。得到的膜曲率与RC-LH1-PufX管状囊泡的大小很好地吻合，并证明了RC-LH1-PufX晚餐的局部曲率特性是如何传播形成所观察到的澳洲央行的远程组织的。球状突起管状小泡。
In the photosynthetic purple bacterium Rhodobacter (Rba.) sphaeroides, light is absorbed by membrane-bound light-harvesting (LH) proteins LH1 and LH2. LH1 directly surrounds the reaction center (RC) and, together with PufX, forms a dimeric (RC-LH1-PufX)(2) protein complex. In LH2-deficient Rba. sphaeroides mutants, RC-LH1-PufX dimers aggregate into tubular vesicles with a radius of similar to 250-550 angstrom, making RC-LH1-PufX one of the few integral membrane proteins known to actively induce membrane curvature. Recently, a three-dimensional electron microscopy density map showed that the Rba. sphaeroides RC-LH1-PufX dimer exhibits a prominent bend at its dimerizing interface. To investigate the curvature properties of this highly bent protein, we employed molecular dynamics simulations to fit an all-atom structural model of the RC-LH1-PufX dimer within the electron microscopy density map. The simulations reveal how the dinner produces a membrane with high local curvature, even though the location of PufX cannot yet be determined uniquely. The resulting membrane curvature agrees well with the size of RC-LH1-PufX tubular vesicles, and demonstrates how the local curvature properties of the RC-LH1-PufX dinner propagate to form the observed long-range organization of the Rba. sphaeroides tubular vesicles.