Molecular dynamics simulations of a protein on hydrophobic and hydrophilic surfaces.
Molecular dynamics simulations of a protein on hydrophobic and hydrophilic surfaces.
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DOI：
10.1016/s0006-3495(96)79497-3
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发表时间：
1996-12
影响因子：
3.4
通讯作者：
D. Tobias;W. Mar;J. Blasie;M. Klein
中科院分区：
文献类型：
--
作者：
D. Tobias;W. Mar;J. Blasie;M. Klein
分子动力学模拟已经被用来研究外周膜蛋白细胞色素c的行为，它共价连接到疏水性(甲基端基)和亲水性(硫醇端基)自组装单分子膜(SAM)上。模拟预测，当蛋白质被拴在任一表面时，它将经历微小的结构变化，并且两个表面上的结构在性质上不同：蛋白质在亲水性SAM上不那么球形，在那里，极性表面残基伸出来与SAM表面相互作用。该蛋白质完全排除在疏水性SAM之外，但部分溶解在亲水性SAM中。因此，尽管在两种自组装膜的主体中都保持了相当高的有序度，但端硫醇封端的自组装膜表面的有序性大大低于端甲基自组装膜的表面有序性：在疏水性和亲水性自组装膜中，链分别以相对于表面法线20度和17度的角度在最近邻方向上集体倾斜。在疏水性的SAM上，蛋白质的取向是使血红素平面更接近于表面，而在亲水性表面上，它更接近垂直。以α螺旋为主的蛋白质的二级结构没有受到显著影响，但环的结构以及螺旋堆积被表面略微改变。
Molecular dynamics simulations have been used to investigate the behavior of the peripheral membrane protein, cytochrome c, covalently tethered to hydrophobic (methyl-terminated) and hydrophilic (thiol-terminated) self-assembled monolayers (SAMs). The simulations predict that the protein will undergo minor structural changes when it is tethered to either surface, and the structures differ qualitatively on the two surfaces: the protein is less spherical on the hydrophilic SAM where the polar surface residues reach out to interact with the SAM surface. The protein is completely excluded from the hydrophobic SAM but partially dissolves in the hydrophilic SAM. Consequently, the surface of the thiol-terminated SAM is considerably less ordered than that of the methyl-terminated SAM, although a comparable, high degree of order is maintained in the bulk of both SAMs: the chains exhibit collective tilts in the nearest-neighbor direction at angles of 20 degrees and 17 degrees with respect to the surface normal in the hydrophobic and the hydrophilic SAMs, respectively. On the hydrophobic SAM the protein is oriented so that the heme plane is more nearly parallel to the surface, whereas on the hydrophilic surface it is more nearly perpendicular. The secondary structure of the protein, dominated by alpha helices, is not significantly affected, but the structure of the loops as well as the helix packing is slightly modified by the surfaces.