Table 1.

The number of water molecules surrounding the PIP2 head group within 6 Angstroms from the phosphates for bound and unbound states as well as the crossing point and three different protonation states. Note that the P4 protonation state is not playing a role at crossing point. Therefore, the number of water molecules is not shown for this state.

	Not protonated	P4 protonated	P5 protonated
Bound	36.0±1.8	32.2±0.9	33.8±1.1
unbound	37.1±2.8	31.1±1.3	35.7±1.6
Crossing point	37.3±0.7	-	31.9±2.0