Tetrapeptide, conformational energetics

Finally, Table 8 presents a comparison of the LMP2 energetics with HF and DFT results for various tetrapeptide conformations. The first interesting observation is that there is... 

A comparison of the predictions of several force fields with ab initio local MP2 predictions of structure and energetics of several conformations of a tetrapeptide [M. D. Beachy et al., J. Am. Chem. Soc., 119,5908 (1997)] foimd the MMFF94, OPLS, and AMBER force fields to give the best stracture predictions and MMFF94 and OPLS fields to give the best energy predictions, but concluded that a truly quantitative prediction of peptide and protein energetics via molecular mechanics is not yet available. ... 

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