Geometry and solvent dependence of the electronic spectra of the amide group and consequences for peptide circular dichroism
Geometry and solvent dependence of the electronic spectra of the amide group and consequences for peptide circular dichroism
Engineering Village 2
? 2006 Elsevier Inc
Accession number: 06199867317
Title: Geometry and solvent dependence of the electronic spectra of the amide group and consequences for peptide circular dichroism
Authors: Sebek, Jiri; Kejik, Zdenek; Bour, Petr
Author affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10, Prague 6, Czech Republic
Serial title: Journal of Physical Chemistry A
Abbreviated serial title: J Phys Chem A
Volume: v 110
Issue: n 14
Issue date: Apr 13 2006
Publication year: 2006
Pages: p 4702-4711
Language: English
ISSN: 1089-5639
CODEN: JPCAFH
Document type: Journal article (JA)
Publisher: American Chemical Society, Columbus, OH 43210-3337, United States
Abstract: The influence of geometry variations and solvent environment of N-methylacetamide on its energies and absorption intensities was systematically analyzed with the aid of the time-dependent density functional theory (TD DFT). Selective and often complicated reactions of individual electronic levels on the perturbations were found important for the resultant spectral profile. For example, the n-p* band position varied by tens of nanometers due to the C=O bond length oscillations, while it was rather unaffected by surrounding water. On the contrary, p-p* type transition energies and intensities were broadly dispersed by the aqueous environment but exhibited a modest coordinate dependence. A simple electrostatic model used previously for absorption in the IR region (J. Chem. Phys. 2005, 122, 144501) explained these changes only partially. Additionally, electronic transfer between the solute and the solvent had to be considered for faithful modeling of the ultraviolet light absorption. The inclusion of the environment and dynamics in the modeling then provided more accurate positions, intensities, and realistic inhomogeneous widths of spectral lines. These factors were found important for absorption and circular dichroism spectra of larger peptides and proteins. This was demonstrated with a combined DFT/coupled oscillator model providing principal features observed in electronic circular dichroism spectra of standard peptide conformations. ? 2006 American Chemical Society.
Number of references: 85
Ei main heading: Proteins
Ei controlled terms: Solvents - Geometry - Chemical bonds - Conformations - Light absorption - Perturbation techniques - Probability density function
Uncontrolled terms: Circular dichroisms - Peptides - Transition energies - Electrostatic model
Ei classification codes: 804.1 Organic Compounds - 803 Chemical Agents and Basic Industrial Chemicals - 921 Applied Mathematics - 801.4 Physical Chemistry - 741.1 Light/Optics - 922.1 Probability Theory
Treatment: Theoretical (THR)
DOI: 10.1021/jp060813v
Database: Compendex
Compilation and indexing terms, ? 2006 Elsevier Inc. All rights reserved
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