Binding Affinities of Amino Acid Analogues at the Charged Aqueous Titania Interface: Implications for Titania-Binding Peptides

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• 作者：Anas M. Sultan ; Zak E. Hughes ; Tiffany R. Walsh
• 刊名：Langmuir
• 出版年：2014
• 出版时间：November 11, 2014
• 年：2014
• 卷：30
• 期：44
• 页码：13321-13329
• 全文大小：398K
• ISSN：1520-5827

文摘

Despite the extensive utilization of biomolecule鈥搕itania 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 鈥渁rginine鈥?> 鈥渓ysine鈥?鈮?aspartic acid > 鈥渟erine鈥? 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鈥揟iO₂ adsorption data.