Our initial study of wild type troponin 21 used a complete model of the human sequence core domain of cTn (419 residues, 6812 atoms), a larger solvent box, and 20-times more sampling than the previous studies but we could not ascertain with statistical significance if phosphorylation changed any of the intra-subunit interactions of cTnI. This could be because a small number of independent MD trajectories of only a few hundred nanoseconds (ns) of length is inadequate but it seemed more likely that phosphorylation and mutations primarily act by altering the dynamics of the troponin molecule in ways that have not been previously analysed .