Campus Units
Chemistry
Document Type
Article
Publication Version
Published Version
Publication Date
9-2008
Journal or Book Title
Journal of Chemical Theory and Computation
Volume
4
Issue
10
First Page
1788
Last Page
1794
DOI
10.1021/ct8002942
Abstract
Quantum chemistry calculations and classical molecular dynamics simulations have been used to examine the equilibria in solution between the neutral and zwitterionic forms of glycine and also of the glycyl radical. The established preference (by 30 kJ mol−1) for the zwitterion of glycine was confirmed by both the quantum chemical calculations and the classical molecular dynamics simulations. The best agreement with experiment was derived from thermodynamic integration calculations of explicitly solvated systems, which gives a free energy difference of 36.6 ± 0.6 kJ mol−1. In contrast, for the glycyl radical in solution, the neutral form is preferred, with a calculated free energy difference of 54.8 ± 0.6 kJ mol−1. A detailed analysis of the microsolvation environments of each species was carried out by evaluating radial distribution functions and hydrogen bonding patterns. This analysis provides evidence that the change in preference between glycine and glycyl radical is due to the inherent gas-phase stability of the neutral α-carbon radical rather than to any significant difference in the solvation behavior of the constituent species.
Copyright Owner
American Chemical Society
Copyright Date
2008
Language
en
File Format
application/pdf
Recommended Citation
Wood, Geoffrey P. F.; Gordon, Mark S.; Radom, Leo; and Smith, David M., "Nature of Glycine and Its α-Carbon Radical in Aqueous Solution: A Theoretical Investigation" (2008). Chemistry Publications. 518.
https://lib.dr.iastate.edu/chem_pubs/518
Comments
Reprinted (adapted) with permission from Journal of Chemical Theory and Computation 4 (2008): 1788, doi:10.1021/ct8002942. Copyright 2008 American Chemical Society.