Divalent Metal Ion Transport across Large Biological Ion Channels and Their Effect on Conductance and Selectivity

Table 1

Ion selectivity of OmpF (WT and mutants) in KCl and CaCl₂.

OmpF channel	Δ𝑞 *	RP (mV); 1/0.1 M KCl	RP (mV); 1/0.1 M CaCl2	Selectivity inversion
WT	0	−25.4±0.8	22.1±0.7	Yes
CC	+2	−23.8±0.8	30.1±1.1	Yes
RR	+4	31.9±1.0	35.4±1.7	No

* Δq: effective charge compared to WT OmpF.