In this work, the influence of membrane curvature on the Ca2+ binding to phospholipid bilayers is investigated by
means of molecular dynamics simulations. In particular, we compared Ca2+ binding to flat, elastically buckled, or uniformly bent
zwitterionic and anionic phospholipid bilayers. We demonstrate that Ca2+ ions bind preferably to the concave membrane surfaces in
both types of bilayers. We also show that the membrane curvature leads to pronounced changes in Ca2+ binding including
differences in free ion concentrations, lipid coordination distributions, and the patterns of ion binding to different chemical groups of
lipids. Moreover, these effects differ substantially for the concave and convex membrane monolayers. Comparison between force
fields with either full or scaled charges indicates that charge scaling results in reduction of the Ca2+ binding to curved
phosphatidylserine bilayers, while for phosphatidylcholine membranes, calcium binds only weakly for both force fields.