. Author manuscript; available in PMC: 2014 Nov 21.

Published in final edited form as: J Chem Theory Comput. 2007 Jul 12;3(5):1721–1733. doi: 10.1021/ct700046j

Table 6.

Effect of Force Field Parameter Set on the Crystallographic Unit Cell Dimensions (Å) for the ala₂ Zwitterion⁵³

AMBER parameter set	isotropic scaling^a
AMBER parameter set	A	B	C	ΔA	ΔB	ΔC	mean \|Δ\|
expt	35.97	35.97	20.62
94	35.47	35.47	20.33	−0.50	−0.50	−0.28	0.43
96	35.50	35.50	20.34	−0.47	−0.47	−0.27	0.41
99	35.52	35.52	20.36	−0.45	−0.45	−0.26	0.39
02	35.44	35.44	20.31	−0.53	−0.53	−0.30	0.45
02EP	35.59	35.59	20.40	−0.38	−0.38	−0.22	0.33
GLYCAM06-LP	36.22	36.22	20.77	0.25	0.25	0.15	0.22

AMBER parameter set	anisotropic scaling^a
AMBER parameter set	A	B	C	ΔA	ΔB	ΔC	mean \|Δ\|
94	35.63	35.63	20.08	−0.34	−0.34	−0.54	0.41
96	35.64	35.64	20.12	−0.33	−0.33	−0.49	0.38
99	35.64	35.64	20.17	−0.33	−0.33	−0.45	0.38
02	36.17	36.16	19.24	0.20	0.19	−1.38	0.59
02EP	37.79	35.10	19.54	1.82	−0.87	−1.07	1.25
GLYCAM06-LP	35.89	35.89	21.23	−0.08	−0.08	0.61	0.26

All simulations with isotropic pressure scaling resulted in standard deviations of 0.01 Å in cell dimensions, while the maximum increase observed with anisotropic scaling was 0.05 Å.