i noticed that ionic interactions are rather weak with Martini 3 compared to Martini 2 polarized model.
I did a simple test with 2 oppositely charged peptides and ran a simulation with reaction-field (epsilon_r 15) and one with PME (epsilon_r 2.5 and non polarized water), both martini 3. The difference is night and day. In the PME version the molecules got attracted right away and remained attracted. With reaction-field only few contacts were made.
is it sensible to use PME with martini 3? I have read about it in literature. maybe it was a mistake to use non polarized water. instead epsilon_r should have remained 15?