Limits...
An In Silico study of TiO 2 nanoparticles interaction with twenty standard amino acids in aqueous solution

View Article: PubMed Central - PubMed

ABSTRACT

Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts. By calculating the Potential Mean Force, we showed that Arg is prone to direct binding onto the NP surface, while Lys needs to overcome a ~2 kT free energy barrier. On the other hand, acidic residues tend to form “water bridges” between their sidechains and TiO2 surface, thus displaying an indirect binding. Moreover, the overall preferred positions and configurations of different residues are highly dependent on properties of the first and second solvation water. These molecular insights learned from this work might help with a better understanding of the interactions between biomolecules and nanomaterials.

No MeSH data available.


Free energy profile of the adsorption the acidic residues Asp and Glu on the TiO2 NP surface and representative configurations (B,C). The H-Bonds in the triad water-amino acid-TiO2 NP, are indicated by green dash lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5121885&req=5

f6: Free energy profile of the adsorption the acidic residues Asp and Glu on the TiO2 NP surface and representative configurations (B,C). The H-Bonds in the triad water-amino acid-TiO2 NP, are indicated by green dash lines.

Mentions: The adsorption free energy profiles for both acidic residues are qualitatively similar and, when compare with the water RDF profile, particularly symmetric but opposite features are evident (Fig. 6A). The Asp profile displays two minima at 1.87 nm (D1) and 2.10 nm (D3) with an in-between maximum at 1.93 nm (D2); in the case of Glu, the corresponding values are: 1.89 nm for E1, 2.12 nm for E3, and 1.94 nm for E2.


An In Silico study of TiO 2 nanoparticles interaction with twenty standard amino acids in aqueous solution
Free energy profile of the adsorption the acidic residues Asp and Glu on the TiO2 NP surface and representative configurations (B,C). The H-Bonds in the triad water-amino acid-TiO2 NP, are indicated by green dash lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5121885&req=5

f6: Free energy profile of the adsorption the acidic residues Asp and Glu on the TiO2 NP surface and representative configurations (B,C). The H-Bonds in the triad water-amino acid-TiO2 NP, are indicated by green dash lines.
Mentions: The adsorption free energy profiles for both acidic residues are qualitatively similar and, when compare with the water RDF profile, particularly symmetric but opposite features are evident (Fig. 6A). The Asp profile displays two minima at 1.87 nm (D1) and 2.10 nm (D3) with an in-between maximum at 1.93 nm (D2); in the case of Glu, the corresponding values are: 1.89 nm for E1, 2.12 nm for E3, and 1.94 nm for E2.

View Article: PubMed Central - PubMed

ABSTRACT

Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts. By calculating the Potential Mean Force, we showed that Arg is prone to direct binding onto the NP surface, while Lys needs to overcome a ~2 kT free energy barrier. On the other hand, acidic residues tend to form “water bridges” between their sidechains and TiO2 surface, thus displaying an indirect binding. Moreover, the overall preferred positions and configurations of different residues are highly dependent on properties of the first and second solvation water. These molecular insights learned from this work might help with a better understanding of the interactions between biomolecules and nanomaterials.

No MeSH data available.