Interfacial water at the trialanine hydrophilic surface: a DFT electronic structure and bottom-up investigation.
نویسندگان
چکیده
DFT-M062X quantum chemical computations on the Ala3H(+)·nH2O (n up to 37) complexes have been performed to model for hydration effects on the molecular properties of protonated trialanine. Following simple rules to arrange water molecules around the peptide, geometry optimization allows us to find four minima corresponding to the unfolded extended (β) and polyproline II (PPII) conformations. The peptide is incorporated into the network of hydrogen bonds of interfacial water molecules with a hydration energy of about -85 kcal mol(-1). The progressive hydration of the peptide shows a more efficient intermolecular hydrogen bonding in the PPII arrangement, and the following relative electronic energy stability β-β < β-PPII ≈ PPII-β < PPII-PPII has been found. The conformational entropy term proceeds in the reverse direction, thus these changes compensate in a way that leads to small changes in Gibbs free energy. These findings agree with experimental data which report an equilibrium between these conformers modulated by temperature.
منابع مشابه
An Experimental Investigation of Water Effects on Asphaltene Surface Behavior through Interfacial Tension Measurements
As a physiochemical property, asphaltenes are known to be one the most surface active compounds in crude oil. Due to such property, their behavior is most probably influenced by fluid-fluid interactions at the contact surface (interface). Potentially and naturally, in most cases, water is in contact with crude oil and is co-produced with it as well. Considering that asphaltene molecules are pol...
متن کاملComputational Investigation of Structure and Reactivity of Methyl Hydrazinecarbodithioate
In this study, we theoretically investigated Methyl hydrazinecarbodithioate by quantum chemical calculations for geometry optimization, vibration frequencies, and electronic structure parameters. The geometry optimization by DFT, ab initio MP2 method and the frequency calculation by DFT method was performed at the highest available Pople style 6-311G++(3df,3pd) basis set level. The semi-emp...
متن کاملInvestingation and Chemisorption study of Oxygen Atoms and Cr (100) surface by DFT calculation
This study concerns about quantum chemical modeling behavior of 02 on Cr (100)surface by using density functional theory (DFT) by LANL2DZ and 6 — 31G* basissets, we presented the results of our first principles electronic structure calculationson the 02 molecules and their interface with Cr (100) surface. The chromium metalhas the body-centered cubic structure, and chromium cluster has five Cr ...
متن کاملProbing Hydrophilic Interface of Solid/Liquid-Water by Nanoultrasonics
Despite the numerous devoted studies, water at solid interfaces remains puzzling. An ongoing debate concerns the nature of interfacial water at a hydrophilic surface, whether it is more solid-like, ice-like, or liquid-like. To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an...
متن کاملFabrication of planar colloidal clusters with template-assisted interfacial assembly.
The synthesis of nanoparticle clusters, also referred to as colloidal clusters or colloidal molecules, is being studied intensively as a model system for small molecule interactions as well as for the directed self-assembly of advanced materials. This paper describes a technique for the interfacial assembly of planar colloidal clusters using a combination of top-down lithographic surface modifi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Physical chemistry chemical physics : PCCP
دوره 17 26 شماره
صفحات -
تاریخ انتشار 2015