Quantifying transient interactions between Bacillus phosphatidylinositol-specific phospholipase-C and phosphatidylcholine-rich vesicles.
Quantifying transient interactions between Bacillus phosphatidylinositol-specific phospholipase-C and phosphatidylcholine-rich vesicles.
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DOI：
10.1021/ja508631n
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发表时间：
2015-01-14
影响因子：
15
通讯作者：
Gershenson, Anne
中科院分区：
文献类型：
--
作者：
Yang, Boqian;Pu, Mingming;Khan, Hanif M.;Friedman, Larry;Reuter, Nathalie;Roberts, Mary F.;Gershenson, Anne
苏云金芽孢杆菌分泌毒力因子磷脂酰肌醇特异性磷脂酶 C (BtPI-PLC)，它与磷脂酰胆碱 (PC) 特异性结合，并从真核细胞质膜上裂解 GPI 锚定蛋白。为了阐明 BtPI-PLC 如何在膜表面搜索 GPI 锚定蛋白，我们测量了单个荧光标记蛋白在富含 PC 的小单层囊泡 (SUV) 上的停留时间。 BtPI-PLC 与 SUV 表面的相互作用是瞬时的，寿命为 379 ± 49 ms。这些数据还表明，BtPI-PLC 并不直接感知曲率，而是更倾向于结合 SUV 中的众多脂质填充缺陷。尽管存在这种对缺陷的偏好，但 BtPI-PLC 与富含 PC 的双层相互作用的全原子分子动力学模拟表明，该蛋白质浅锚定在双层中心上方 ∼18 Å 的最深插入位置。膜分配平均由 41 个疏水、8 个氢键和 2 个阳离子-π（PC 胆碱头基和 Tyr 残基之间）与磷脂的瞬时相互作用介导。这些结果得出了 BtPI-PLC 与细胞膜相互作用的定量模型，其中蛋白质结合是由脂质堆积缺陷介导的，可能靠近 GPI 锚定蛋白，并且蛋白质在膜上扩散约 100–380 ms，在此期间它可能在解离前裂解约 10 个 GPI 锚定蛋白。这种短二维滑行和三维跳跃的组合可能是在有障碍物的二维表面上的有效搜索策略。
Bacillus thuringiensis secretes the virulence factor phosphatidylinositol-specific phospholipase C (BtPI-PLC), which specifically binds to phosphatidylcholine (PC) and cleaves GPI-anchored proteins off eukaryotic plasma membranes. To elucidate how BtPI-PLC searches for GPI-anchored proteins on the membrane surface, we measured residence times of single fluorescently labeled proteins on PC-rich small unilamellar vesicles (SUVs). BtPI-PLC interactions with the SUV surface are transient with a lifetime of 379 ± 49 ms. These data also suggest that BtPI-PLC does not directly sense curvature, but rather prefers to bind to the numerous lipid packing defects in SUVs. Despite this preference for defects, all-atom molecular dynamics simulations of BtPI-PLC interacting with PC-rich bilayers show that the protein is shallowly anchored with the deepest insertions ∼18 Å above the bilayer center. Membrane partitioning is mediated, on average, by 41 hydrophobic, 8 hydrogen-bonding, and 2 cation−π (between PC choline headgroups and Tyr residues) transient interactions with phospholipids. These results lead to a quantitative model for BtPI-PLC interactions with cell membranes where protein binding is mediated by lipid packing defects, possibly near GPI-anchored proteins, and the protein diffuses on the membrane for ∼100–380 ms, during which time it may cleave ∼10 GPI-anchored proteins before dissociating. This combination of short two-dimensional scoots followed by three-dimensional hops may be an efficient search strategy on two-dimensional surfaces with obstacles.
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影响因子：
15
作者：
Grauffel C;Yang B;He T;Roberts MF;Gershenson A;Reuter N
通讯作者：
Reuter N
影响因子：
3.4
作者：
Vamparys, Lydie;Gautier, Romain;Fuchs, Patrick F. J.
通讯作者：
Fuchs, Patrick F. J.
影响因子：
2.9
作者：
Zhou, C;Qian, XQ;Roberts, MF
通讯作者：
Roberts, MF
影响因子：
2.9
作者：
Pu, Mingming;Roberts, Mary F.;Gershenson, Anne
通讯作者：
Gershenson, Anne
影响因子：
4.4
作者：
Zenewicz, LA;Wei, ZY;Shen, H
通讯作者：
Shen, H