Sultan Anas M, Hughes Zak E, Walsh Tiffany R
Institute for Frontier Materials, Deakin University , Geelong, VIC 3216, Australia.
Langmuir. 2014 Nov 11;30(44):13321-9. doi: 10.1021/la503312d. Epub 2014 Oct 28.
Despite the extensive utilization of biomolecule-titania interfaces, biomolecular recognition and interactions at the aqueous titania interface remain far from being fully understood. Here, atomistic molecular dynamics simulations, in partnership with metadynamics, are used to calculate the free energy of adsorption of different amino acid side chain analogues at the negatively-charged aqueous rutile TiO2 (110) interface, under conditions corresponding with neutral pH. Our calculations predict that charged amino acid analogues have a relatively high affinity to the titania surface, with the arginine analogue predicted to be the strongest binder. Interactions between uncharged amino acid analogues and titania are found to be repulsive or weak at best. All of the residues that bound to the negatively-charged interface show a relatively stronger adsorption compared with the charge-neutral interface, including the negatively-charged analogue. Of the analogues that are found to bind to the titania surface, the rank ordering of the binding affinities is predicted to be "arginine" > "lysine" ≈ aspartic acid > "serine". This is the same ordering as was found previously for the charge-neutral aqueous titania interface. Our results show very good agreement with available experimental data and can provide a baseline for the interpretation of peptide-TiO2 adsorption data.
尽管生物分子 - 二氧化钛界面得到了广泛应用，但在二氧化钛水界面上的生物分子识别和相互作用仍远未得到充分理解。在此，原子分子动力学模拟与元动力学相结合，用于计算在中性pH条件下，不同氨基酸侧链类似物在带负电荷的金红石型TiO₂(110)水界面上的吸附自由能。我们的计算预测，带电荷的氨基酸类似物对二氧化钛表面具有相对较高的亲和力，其中精氨酸类似物预计是最强的结合剂。发现不带电荷的氨基酸类似物与二氧化钛之间的相互作用充其量是排斥性的或微弱的。与电荷中性界面相比，所有与带负电荷界面结合的残基都表现出相对更强的吸附，包括带负电荷的类似物。在被发现与二氧化钛表面结合的类似物中，结合亲和力的排序预计为“精氨酸”>“赖氨酸”≈天冬氨酸>“丝氨酸”。这与之前在电荷中性的二氧化钛水界面上发现的排序相同。我们的结果与现有实验数据非常吻合，并可为解释肽 - TiO₂吸附数据提供基线。
