Nature of Molecular Interactions of Peptides with Gold, Palladium, and Pd-Au Bimetal Surfaces in Aqueous Solution
Nature of Molecular Interactions of Peptides with Gold, Palladium, and Pd-Au Bimetal Surfaces in Aqueous Solution
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DOI：
10.1021/ja900531f
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发表时间：
2009-07-22
影响因子：
15
通讯作者：
Naik, Rajesh R.
中科院分区：
文献类型：
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作者：
Heinz, Hendrik;Farmer, Barry L.;Naik, Rajesh R.
我们研究了噬菌体展示技术衍生的几种短肽（8-12 个氨基酸，不包括 Cys）与 Au、Pd 和 Pd-Au 双金属表面选择性结合所涉及的分子相互作用。通过分子动力学模拟，使用有效的计算筛选技术，对吸附在{111}和{100}表面上时的能量和构象变化进行定量分析，包括1000个显式水分子和pH = 7时具有物理意义的肽浓度。在多个纳秒的过程中从溶液到吸附状态的链构象变化表明肽优选与金属表面上方面心立方晶格的空位相互作用。有助于结合的残留物与金属表面直接接触，而较少结合的残留物则通过一层或两层水层与表面隔开。吸附强度范围为 0 至 -100 kcal/（mol 肽），并与金属的表面能（Pd 表面比 Au 表面更具吸引力）、单个残基的亲和力与水的亲和力、构象方面以及金属界面处的极化和电荷转移（此处仅定性考虑）成正比。 {111} 表面上可用晶格位点之间大约 1.6 埃的六边形间距解释了芳香族侧基和各种其他残基（包括 Tyr、Phe、Asp、His、Arg、Asn、Ser）的特征吸附，而 {100} 表面上可用晶格位点之间大约 2.8 埃的二次方间距说明了对所有肽的亲和力明显较低，有利于移动水分子。这些因素的结合表明了一种“软外延”的结合机制。在双金属 Pd-Au {111} 表面上，结合模式相似，双金属结的极性可以将结合能改变约 10 kcal/mol。该结果得到了肽和小分子与金属表面亲和力的实验测量以及小肽和表面片段的量子力学计算结果的半定量支持。使用针对 fcc 金属的 Lennard-Jones 参数扩展的一致价态力场对界面进行建模，该场可以准确地再现表面和界面能量 [Heinz, H.;瓦亚，R.A.；农夫，B.L.； Naik，R.R.J. 物理学。化学。 C 2008, 112, 17281-17290]。
We investigated molecular interactions involved in the selective binding of several short peptides derived from phage-display techniques (8-12 amino acids, excluding Cys) to surfaces of Au, Pd, and Pd-Au bimetal. The quantitative analysis of changes in energy and conformation upon adsorption on even {111} and {100} surfaces was carried out by molecular dynamics simulation using an efficient computational screening technique, including 1000 explicit water molecules and physically meaningful peptide concentrations at pH = 7. Changes in chain conformation from the solution to the adsorbed state over the course of multiple nanoseconds suggest that the peptides preferably interact with vacant sites of the face-centered cubic lattice above the metal surface. Residues that contribute to binding are in direct contact with the metal surfaces, and less-binding residues are separated from the surface by one or two water layers. The strength of adsorption ranges from 0 to -100 kcal/(mol peptide) and scales with the surface energy of the metal (Pd surfaces are more attractive than Au surfaces), the affinity of individual residues versus the affinity of water, and conformation aspects, as well as polarization and charge transfer at the metal interface (only qualitatively considered here). A hexagonal spacing of similar to 1.6 angstrom between available lattice sites on the {111} surfaces accounts for the characteristic adsorption of aromatic side groups and various other residues (including Tyr, Phe, Asp, His, Arg, Asn, Ser), and a quadratic spacing of similar to 2.8 angstrom between available lattice sites on the {100} surface accounts for a significantly lower affinity to all peptides in favor of mobile water molecules. The combination of these factors suggests a "soft epitaxy" mechanism of binding. On a bimetallic Pd-Au {111} surface, binding patterns are similar, and the polarity of the bimetal junction can modify the binding energy by similar to 10 kcal/mol. The results are semiquantitatively supported by experimental measurements of the affinity of peptides and small molecules to metal surfaces as well as results from quantum-mechanical calculations on small peptide and surface fragments. Interfaces were modeled using the consistent valence force field extended for Lennard-Jones parameters for fcc metals which accurately reproduce surface and interface energies [Heinz, H.; Vaia, R. A.; Farmer, B. L.; Naik, R. R. J. Phys. Chem. C 2008, 112, 17281-17290].