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During the course of MD in a bound structure, NH2 of the sulfonamide is being pulled in close to the SO2 oxygens. The O-S-N angles go down to around 72 degrees and the distance between oxygen and hydrogen goes down to around 1.7 angstroms.
Test simulation with a simple sulfonamide in water showed the same pathology, while it did not happen when using SMIRNOFF99Frosst.
Parsley parameters
SMIRNOFF99Frosst | Parsley 1.2 | Parsley 1.3 | |
|---|---|---|---|
a30 | 109.5 / 140.0 | 104.2 / 201.1 | 99.1 / 220.7 |
a31 | 109.5 / 120.0 | 96.3 / 152.3 | 89.8 / 188.4 |
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