Dear GROMACS users,<br><br>I am working on a cyclic peptide dynamics in DMSO solvent box with ffG53a6 force filed. As the results are not satisfactory, I have carried out the MD by restraining couple of hydrogen bonds. However, the results are same as unrestrained calculations when I used the "fac" values of 1 or 2, which correspond to force constants of 1000 kJ/mol or 2000 kJ/mol. <br>
<br>Could you please clarify me regarding the optimum and the highest value that can be used for "fac", which is the multiplication factor for disres_fc ( = 1000 kJ/mol).<br><br>Could you also inform about the forcefield that best handles the DMSO solvent box MD runs and also hydrogen bonds.<br>
<br>yours sincerely,<br>uday.<br>