Simulations run with OpenMM shared all of the MD setup parameters with their GROMACS counterparts, with the exception of using a different constraint algorithm. Constant Constraint Matrix Approximation (CCMA) was used instead of LINCS. The Martini implementation in OpenMM has been shown to offer excellent agreement between OpenMM and GROMACS in single-step force and energy calculations, with only small differences arising in ensemble averages .