Characterization and Three-Dimensional Structural Modeling of Humic Acid Using Molecular Dynamics
The humic acid (HA) was obtained from an alluvial soil from the experimental station of under conservation tillage in Luancheng County,Hebei Province,China is the object of this study.HA was characterized by elemental composition,infrared and 13C-nuclear magnetic resonance (NMR) spectroscopy.ChemBioOffice was used to construct the two-dimensional molecular structure of the HA monomers.By comparing the actual and simulated spectra,we determined that the two-dimensional structure of the HA molecular model had better suitability.This study also used HyperChem to simulate the three-dimensional molecular structure of the monomers,which was optimized by the molecular mechanics of the MM+,AMBER,and OPLS force fields.After optimization,the bond energy,bond-angle energy,dihedral-angle energy,van der Waals energy,electrostatic energy,and total potential energy were all found to have changed,which show no rules during the variation.At the same time,a molecular dynamics simulation was also used.Under the OPLS force field,the three-dimensional structure of the HA monomers had the smallest heat of formation (-1,485.99 kJ/mol),which indicates that it is the most stable of the three force fields.The molecular structure and total potential energy in the simulated environment changed after optimization,but all of the various energy states were generally stable.
Alluvial soil Humic acid Molecular simulation Three-dimensional structure OPLS force field
Nan Zhao Yintian Zheng Yizhong Lv
College of Resources and Environmental Sciences,China Agricultural University,Beijing 100193,P.R.China
国际会议
the 16th Meeting of the International Humic Substances Society (第十六届国际腐殖物质学会大会(IHSS 16))
杭州
英文
103-104
2012-09-09（万方平台首次上网日期，不代表论文的发表时间）