title: Development of a group contribution method for estimating free energy of peptides in a dodecane-water system via molecular dynamic simulations.
abstract: BACKGROUND
  Calculation of the Gibbs free energy changes of biological molecules at the oil-water interface is commonly performed with Molecular Dynamics simulations (MD). It is a process that could be performed repeatedly in order to find some molecules of high stability in this medium. Here, an alternative method of calculation has been proposed: a group contribution method (GCM) for peptides based on MD of the twenty classic amino acids to obtain free energy change during the insertion of any peptide chain in water-dodecane interfaces. Multiple MD of the twenty classic amino acids located at the interface of rectangular simulation boxes with a dodecane-water medium were performed.
  
  
  RESULTS
  A GCM to calculate the free energy of entire peptides is then proposed. The method uses the summation of the Gibbs free energy of each amino acid adjusted in function of its presence or absence in the chain as well as its hydrophobic characteristics.
  
  
  CONCLUSIONS
  Validation of the equation was performed with twenty-one peptides all simulated using MD in dodecane-water rectangular boxes in previous work, obtaining an average relative error of 16%.
authors.affiliation: Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes, Carrera 1E No. 19A-40, Edificio Mario Laserna, Bogotá, DC, Colombia.
authors.forename: Camilo Andrés
authors.initials: CA
authors.lastname: Mora Osorio
authors.affiliation: Grupo de Diseño de Productos y Procesos (GDPP), Departamento de Ingeniería Química, Universidad de los Andes, Carrera 1E No. 19A-40, Edificio Mario Laserna, Bogotá, DC, Colombia. andgonza@uniandes.edu.co.
authors.forename: Andrés Fernando
authors.initials: AF
authors.lastname: González Barrios
mesh_terms: D000473:Alkanes / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D056004:Molecular Dynamics Simulation; D010455:Peptides / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000473:Alkanes; D000596:Amino Acids; D010455:Peptides; D014867:Water; C007548:n-dodecane
keywords: Free energy calculations; Group contribution method; Molecular dynamics; Residues chain