Caracterização e funcionalização de aminoácidos em nanoestruturas 3d de carbono tipo Cx (X = 60 e 70).

Abstract

Amino acids are the fundamental structural units of proteins and peptides, and are essential for the human body. Functionalization with amino acids increases solubility of fullerenes in water and aqueous solutions, therefore, it has several applications, especially biological ones. In this sense, this work aims to characterize the nonpolar essential amino acid molecules (alanine, isoleucine, phenylalanine and valine) and its functionalization with fullerenes C50, C60 and C70, through computational simulations based on Molecular Dynamics (with UFF) and DFT (with LDA-PWC and GGA-PBE). Firstly, an individual structural analysis of each amino acid molecule was carried out, including determining bond lengths, bond angles and torsions. In addition Furthermore, the properties of the frontier molecular orbitals, the density of states and adsorption capacity of amino acids in relation to fullerene. That was carried out by calculating the potential interaction energies of the distance between the centroids, both from a quantum and classical perspective. As a result, the functional GGA-PBE presented the lowest energy for the four amino acids. It was observed a predominance of the HOMO orbitals in the amino group and the LUMO orbital in the carbonyl and phenyl ring (for phenylalanine). The simulation with the C60 and C70 fullerenes together with the amino acids were successful, except with C50 as it is very unstable and the bonds were broken down in quantum calculation. Thus, the results obtained through simulations were satisfactory and allowed us to obtain the properties of the studied amino acids and their adsorption with fullerenes, aiming to increase the solubility of fullerenes.