The J coupling errors for ubiquitin and GB3 are summarized in Table . With an overall RMSE of 1.54 Hz, the error using the QUBE force field for ubiquitin is higher than that of OPLS-AA/M, which has an RMSE of 1.12 Hz, but lower than OPLS-AA and OPLS-AA/L with errors of 1.84 Hz and 1.70 Hz respectively. 1 GB3 follows the same trend with an RMSE of 1.10 Hz for the QUBE force field, compared to the error for OPLS-AA/M of 0.90 Hz, whilst OPLS-AA and OPLS-AA/L both have an error of 1.46 Hz. 1 The J coupling results suggest that whilst the transfer of torsional parameters from dipeptides to proteins may cause some issues, the QUBE force field remains more accurate than OPLS-AA and OPLS-AA/L. This is promising when we consider that OPLS has been in development for many years with multiple iterations and parameter adjustments performed.