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Facet-Specific Adsorption of Tripeptides at Aqueous Au Interfaces: Open Questions in Reconciling Experiment and Simulation
journal contribution
posted on 2017-04-18, 00:00 authored by Zak Hughes, Raji Kochandra, Tiffany WalshTiffany WalshThe adsorption of three homo-tripeptides, HHH, YYY, and SSS, at the aqueous Au interface is investigated, using molecular dynamics simulations. We find that consideration of surface facet effects, relevant to experimental conditions, opens up new questions regarding interpretations of current experimental findings. Our well-tempered metadynamics simulations predict the rank ordering of the tripeptide binding affinities at aqueous Au(111) to be YYY > HHH > SSS. This ranking differs with that obtained from existing experimental data which used surface-immobilized Au nanoparticles as the target substrate. The influence of Au facet on these experimental findings is then considered, via our binding strength predictions of the relevant amino acids at aqueous Au(111) and Au(100)(1 × 1). The Au(111) interface supports an amino acid ranking of Tyr > HisA ≃ HisH > Ser, matching that of the tripeptides on Au(111), while the ranking on Au(100) is HisA > Ser ≃ Tyr ≃ HisH, with only HisA showing non-negligible binding. The substantial reduction in Tyr amino acid affinity for Au(100) vs Au(111) offers one possible explanation for the experimentally observed weaker adsorption of YYY on the nanoparticle-immobilized substrate compared with HHH. In a separate set of simulations, we predict the structures of the adsorbed tripeptides at the two aqueous Au facets, revealing facet-dependent differences in the adsorbed conformations. Our findings suggest that Au facet effects, where relevant, may influence the adsorption structures and energetics of biomolecules, highlighting the possible influence of the structural model used to interpret experimental binding data.
History
Journal
LangmuirVolume
33Issue
15Pagination
3742 - 3754Publisher DOI
ISSN
0743-7463eISSN
1520-5827Publication classification
C1 Refereed article in a scholarly journalCopyright notice
2017, American Chemical SocietyUsage metrics
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No categories selectedKeywords
Science & TechnologyPhysical SciencesTechnologyChemistry, MultidisciplinaryChemistry, PhysicalMaterials Science, MultidisciplinaryChemistryMaterials ScienceGOLD-BINDING PEPTIDESMOLECULAR-DYNAMICSFORCE-FIELDSNANOPARTICLE SYNTHESISMETAL NANOPARTICLESINORGANIC SURFACESAMINO-ACIDSPROTEINSSEQUENCEAU(111)adsorptiontripeptidesaqueous Au interfacemolecular dynamics simulationssurface facet effectstripeptide binding affinitiesaqueous Au(111)HHHYYYSSSbiomoleculesexperimental binding datastructural model
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