Table 4.
Scalar couplings of the central residue (Ala 10) of HEWL19 for different force fields. The lower part of the table lists the Ramachandran populations and fraction helix averaged over the three consecutive Ala residues (errors in parentheses), and the χ2 relative to the experimental J-couplings (complete data for Ala 9, 10, and 11 are given in SI Table 3).
| Expt. | σ | ff03 | ff99SB | ff03* | ff99SB* | |
|---|---|---|---|---|---|---|
| A10 1JNCα(ψ10) | 10.58 | 0.59 | 10.04 | 10.84 | 10.51 | 10.27 |
| A10 2JNCα(ψ9) | 7.24 | 0.50 | 6.48 | 7.50 | 7.43 | 7.06 |
| A10 3JHαC(ϕ10) | 1.72 | 0.38 | 1.40 | 2.55 | 1.55 | 1.82 |
| A10 3JHNC(ϕ10) | 1.33 | 0.59 | 0.58 | 1.10 | 1.00 | 0.65 |
| A10 3JHNCβ(ϕ10) | 2.19 | 0.39 | 3.48 | 2.23 | 2.86 | 3.01 |
| A10 3JHNHα(ϕ10) | 5.10 | 0.91 | 5.72 | 7.08 | 5.95 | 6.46 |
| A103JHNCα(ϕ10; ψ9) | 0.46 | 0.10 | 0.24 | 0.52 | 0.46 | 0.39 |
| % α+ | 91.6 (1.6) | 34.9 (2.3) | 60.6 (2.3) | 69.4 (2.5) | ||
| % β | 1.8 (0.7) | 23.5 (1.3) | 15.8 (1.7) | 12.9 (1.3) | ||
| % ppII | 6.3 (1.3) | 27.9 (1.5) | 22.6 (1.3) | 15.2 (1.6) | ||
| % helix | 78.6 (2.5) | 4.5 (1.0) | 35.1 (2.3) | 30.9 (2.0) | ||
| χ2(J) | 3.2 | 1.3 | 1.0 | 1.0 | ||