Accurate ab Initio Quantum Chemical Determination of the Relative Energetics of Peptide Conformations and Assessment of Empirical Force Fields
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- 作者：Michael D. Beachy ; David Chasman ; Robert B. Murphy ; Thomas A. Halgren ; and Richard A. Friesner
- 刊名：Journal of the American Chemical Society
- 出版年：1997
- 出版时间：June 25, 1997
- 年：1997
- 卷：119
- 期：25
- 页码：5908 - 5920
- 全文大小：340K
- 年卷期：v.119,no.25(June 25, 1997)
- ISSN：1520-5126
文摘
Correlated ab initio calculations have been carried outwith a parallel version of the PSGVB electronicstructure code to obtain relative energetics of a number ofconformations of the alanine tetrapeptide. Thehighestlevel of theory utilized, local MP2 with the cc-pVTZ(-f)correlation-consistent basis set, has previously beenshownto provide accurate conformational energies in comparison withexperiment for a data set of small molecules.Comparisons with published and new canonical MP2 calculations onthe alanine dipeptide are made. Results for tengas-phase tetrapeptide conformations and a 
ddle">-sheet dipeptide dimerare compared with 20 different molecular mechanicsforce field parametrizations, providing the first assessment of thereliability of these models for systems larger thana dipeptide. Comparisons are made with the LMP2/cc-pVTZ(-f)results, which are taken as a benchmark for thetetrapeptides. Statistical summaries with regard to energetics andstructure are produced for each force field, and adiscussion of qualitative successes and failures is provided. Theresults display both the successes and limitationsof the force fields studied and can be used as benchmark data in thedevelopment of new and improved force fields.In particular, comparisons of hydrogen-bonding energetics as afunction of geometry suggest that future force fieldswill need to employ a representation for electrostatics that goesbeyond the use of atom-centered partial charges.
ddle">-sheet dipeptide dimerare compared with 20 different molecular mechanicsforce field parametrizations, providing the first assessment of thereliability of these models for systems larger thana dipeptide. Comparisons are made with the LMP2/cc-pVTZ(-f)results, which are taken as a benchmark for thetetrapeptides. Statistical summaries with regard to energetics andstructure are produced for each force field, and adiscussion of qualitative successes and failures is provided. Theresults display both the successes and limitationsof the force fields studied and can be used as benchmark data in thedevelopment of new and improved force fields.In particular, comparisons of hydrogen-bonding energetics as afunction of geometry suggest that future force fieldswill need to employ a representation for electrostatics that goesbeyond the use of atom-centered partial charges.