Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/327283
Type: Artigo
Title: Qtaim-based Characteristic Group Infrared Intensities Of Amino Acids And Their Transference To Peptides
Author: Silva
Arnaldo F.; Duarte
Leonardo J.; Bruns
Roy E.
Abstract: Dynamic atomic contributions (DACs) to the infrared intensities of 14 amino acids have been transferred to three peptide molecules, glycylglycine, trialanine, and the melanocyte-inhibiting factor MIF-1, to estimate the infrared intensities of the most strategic peptide bands. The DACs of the amino acids and infrared intensities of the peptides were determined at the DFT B3LYP/6-311+(d,p) level. The Quantum Theory of Atoms In Molecules (QTAIM) Charge Charge Transfer Dipolar Polarization (CCTDP) model at this Density Functional Theory (DFT) level was used to classify the O-H, NH2, N-H, and C=O stretching as well as the NH2 bending characteristic groups for use in the transference procedure. Contrary to the frequencies, the intensities within these groups can have very diverse values, although their electronic structure changes upon vibration have predictable QTAIM behaviors for each group. Compared to the DFT calculated values, the two transferred O-H stretching intensities of the peptides are estimated with a root-mean-square (rms) error of 19.1 km mol(-1). Six NH2 symmetric and antisymmetric stretching intensities were determined with a 9.9 km mol(-1) error. The eight estimated C=O stretching bands have a rms error of 78.0 km mol(-1) or 23.6% of the average DFT peptide C=O intensity of 328.4 km mol(-1). The proposed procedure is applicable to experimental infrared intensities if a calibration set of molecules with known atomic polar tensors and normal coordinate transformations is available.
Subject: Force-field
Quantum-theory
Fundamental Intensities
Molecules
Atoms
Model
Water
Spectroscopy
Trialanine
Amber
Editor: Amer Chemical Soc
Washington
Rights: fechado
Identifier DOI: 10.1021/acs.jpca.6b07690
Address: http://pubs-acs-org.ez88.periodicos.capes.gov.br/doi/abs/10.1021/acs.jpca.6b07690
Date Issue: 2016
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
000386641400018.pdf1.98 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.