Theoretical Study of the Adsorption Mechanism of Cystine on Au(110) in Aqueous Solution.
The adsorption and dynamics of cystine, which is the oxidized dimer of cysteine where the monomers are connected through a disulfide bond, on the Au(110) surface, in water solution, is characterized by means of classical molecular dynamics simulations based on a recently developed reactive force field (ReaxFF). The adopted computational procedure and the force field description are able to give a complete and reliable picture, in line with experiments, of the molecule behavior in solution and in close contact with the metal support. Many different aspects, which have never been explored computationally at this level of theory, are disclosed, namely, physisorption, chemisorption, disulfide bridge breaking/creation, and formation of staples. It is demonstrated that all these events are connected with the specific orientation and location of cystine on the substrate. Simulations in pure water reveal that the disulfide bridge is stable, whereas dissociation is observed on gold. This is favored at low coverage, whereas at high coverage both intact and dissociated forms can be observed depending on local arrangements. The computed photoemission spectra at different K-edges for the predicted adsorbate structures satisfactorily agree with the experimental measurements extracted from literature.
CNR-ICCOM, Institute of Chemistry of Organometallic Compounds, via G. Moruzzi 1, I-56124, Pisa, Italy.|Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-106 91, Stockholm, Sweden.
Susanna
S
Monti
CNR-IPCF, Institute of Chemical and Physical Processes, via G. Moruzzi 1, I-56124, Pisa, Italy.
Vincenzo
V
Carravetta
Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH Royal Institute of Technology, SE-106 91, Stockholm, Sweden.
Hans
H
Ågren
D000327:Adsorption; D003553:Cystine / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008962:Models, Theoretical; D056004:Molecular Dynamics Simulation; D056951:Photoelectron Spectroscopy; D012996:Solutions; D055672:Static Electricity; D014867:Water / Q000737:chemistry*
D004220:Disulfides; D012996:Solutions; D014867:Water; D003553:Cystine; D006046:Gold; D006859:Hydrogen
biocompatibility; gold nanoparticle stabilization; hybrid materials; peptide-metal binding