Table 1. Differences in the Molecular Mechanics (MM) Energy Components for 628 Conformations of Various Dipeptides after Optimization by MM or MP2/6-31++G^a.

dipeptide	bond	angle	1–4 LJ	1–4 elec	other LJ	other elec	bonded sumb	nonbonded sumc
Ash	2.99 ± 0.34	0.66 ± 0.98	0.96 ± 0.17	2.20 ± 1.25	0.28 ± 0.41	–1.88 ± 1.00	3.65 ± 1.15	1.57 ± 1.06
Asn	2.08 ± 0.45	0.56 ± 0.90	0.93 ± 0.15	4.16 ± 1.28	0.24 ± 0.40	–2.88 ± 1.25	2.64 ± 2.06	2.45 ± 1.01
Asp	1.92 ± 0.38	1.08 ± 0.55	0.88 ± 0.16	2.60 ± 1.01	0.58 ± 0.34	–1.98 ± 1.16	3.00 ± 0.65	2.08 ± 0.48
Cys	1.63 ± 0.24	1.46 ± 0.77	0.46 ± 0.26	2.71 ± 0.89	0.43 ± 0.14	–2.45 ± 0.80	3.09 ± 0.83	1.15 ± 0.44
Hid	3.21 ± 0.33	3.02 ± 1.03	0.83 ± 0.17	2.27 ± 0.81	0.24 ± 0.31	–2.06 ± 0.75	6.23 ± 1.05	1.28 ± 0.53
Hie	2.93 ± 0.26	2.62 ± 1.04	0.92 ± 0.17	2.71 ± 0.79	0.34 ± 0.31	–2.32 ± 0.75	5.55 ± 1.05	1.65 ± 0.47
Hip	3.17 ± 0.45	2.99 ± 1.17	1.10 ± 0.16	3.43 ± 0.95	0.70 ± 0.46	–2.61 ± 0.90	6.16 ± 1.42	2.61 ± 1.06
Ile	1.36 ± 0.29	0.89 ± 0.61	0.89 ± 0.17	2.20 ± 0.62	0.62 ± 0.58	–2.04 ± 0.49	2.25 ± 0.70	1.67 ± 0.72
Leu	1.47 ± 0.30	1.13 ± 0.59	0.64 ± 0.14	3.23 ± 0.89	0.31 ± 0.45	–2.78 ± 0.73	2.60 ± 0.70	1.40 ± 0.56
Phe	1.77 ± 0.26	0.92 ± 0.69	1.73 ± 0.18	2.34 ± 0.76	0.45 ± 0.52	–2.21 ± 0.65	2.69 ± 0.76	2.32 ± 0.62
Ser	1.59 ± 0.26	0.48 ± 0.33	0.95 ± 0.36	2.04 ± 0.73	0.49 ± 0.09	–1.83 ± 0.67	2.07 ± 0.42	1.64 ± 0.49
Thr	1.59 ± 0.27	0.46 ± 0.33	0.99 ± 0.42	2.84 ± 0.99	0.47 ± 0.12	–2.30 ± 0.86	2.05 ± 0.43	2.00 ± 0.63
Trp	2.39 ± 0.28	2.85 ± 1.02	1.64 ± 0.19	2.64 ± 0.78	0.48 ± 0.80	–2.31 ± 0.79	5.24 ± 1.07	2.44 ± 0.81
Tyr	2.16 ± 0.26	1.36 ± 0.70	1.88 ± 0.18	2.37 ± 0.76	0.43 ± 0.59	–2.39 ± 0.66	3.52 ± 0.79	2.29 ± 0.70
Val	1.42 ± 0.25	0.75 ± 0.25	0.70 ± 0.13	2.71 ± 0.54	0.40 ± 0.12	–2.32 ± 0.46	2.17 ± 0.30	1.48 ± 0.28

^aEach difference is given as an average ± standard deviation, in kcal/mol.

^bIncludes bond and angle contributions.

^cIncludes Lennard–Jones (LJ) and electrostatic (elec) contributions.