As reported in the literature, the C2B polybasic region KRLKKKKTTIKK (positions 321-332) and the arginine pair (R398,R399) are key during large membrane remodeling processes mediated by Syt1, such as fusion and pore expansion. In particular, the polybasic patch in C2B binds to negatively charged lipids, such as PIP 2 clusters, in a calcium-independent manner. Although in the atomistic space the inclusion of Ca 2+ ions to model the penetration depth of the C2B binding loop would be in principle the right approach, with coarse-grained models the strategy is not straightforward. In the reduced resolution space, the parameterization of metal ions is still approximated or unavailable for the most of coarse-grained force fields. For Martini, ions are modeled with single beads representing both the ion itself and the first hydration shell. Therefore, in this work we have described Syt1-C2B binding mechanisms in a calcium-independent manner.