Table I.

List of Modified Parameters for the χ₁ and χ₂ Torsion Potentials in Selected Amino Acids of the Amber ff99SB Force Field

Res.	Angle	θ0	k1	k2	k3	k4	k5	k6
Ile	N–Cα–Cβ–Cγ2	0.0	0.195	−0.846
Leu	C–Cα–Cβ–Cγ	0.0	0.571	−0.358	0.135
Asp	N–Cα–Cβ–Cγ	0.0	−2.635	−1.190	−0.007	0.423	0.232	−0.213
	Cα–Cβ–Cγ–Oδ1,2	0.0	0.0	−0.443	0.0	−0.138	0.0	−0.013
Asn	C–Cα–Cβ–Cγ	0.0	0.571	−0.596	0.118	−0.417	0.104	−0.101
	Cα–Cβ–Cγ–Nδ	0.0	−1.046	−0.181	−0.035	0.100	0.130	−0.106

The parameters are in kcal mol⁻¹ and correspond to the torsion potentials that are defined in the main text. Note that for the χ₂ torsion in Asp, the correction is applied to both side-chain oxygen atoms.