Table 5. Quantification of interfaces within the γ-carbonic-anhydrase (γCA) domain and between γCA and the proximal pumping domain (P_P) of CI*.

Interface residues, surface areas, solvation free energies and P-values were determined by uploading the molecular model of CI* into the the PDBePISA tool for the exploration of macromolecular interfaces (Krissinel and Henrick, 2007). The table with the full list of interaction surfaces for CI* was filtered for the interfaces involving CA1, CA2 or CAL2. Total values were obtained by adding the relevant two-way interactions, as per PDBePISA guidelines.

Subunit 1			Subunit 2			Inter-subunit interface
Subunit	# Interfacing residues	Interfacing surface area (Å2)	Subunit	# Interfacing residues	Interfacing surface area (Å2)	Interface surface area (Å2)	Interface solvation free energy (kcal/mol)	Solvation free energy gain P-value
Within γCA domain
CA1	88	20,989	CA2	80	22,088	2581.4	−45.6	0.000
CA1	79	20,989	CAL2	72	20,073	2637.8	−38.2	0.001
CA2	73	22,088	CAL2	66	20,073	2148.1	−33.2	0.000
					Total	7367.3	−117
Between γCA domain and membrane arm (PP)
NU2M	16	7610	CA1	16	20,989	259.2	−17.1	0.001
NU2M	16	7610	CA2	16	22,088	261.1	−17.1	0.001
NU2M	16	7610	CAL2	16	20,073	263.6	−18.0	0.003
NDUC2	21	13,708	CA1	21	20,989	427.8	−20.2	0.000
NDUC2	16	13,708	CA2	16	22,088	242.3	−15.8	0.000
NDUC2	21	13,708	CAL2	22	20,073	416.2	−18.7	0.000
P2	21	10,433	CA1	21	20,989	362.6	−16.5	0.000
P2	26	10,433	CA2	22	22,088	512.7	−21.5	0.001
P2	17	10,433	CAL2	17	20,073	244.6	−16.8	0.001
NDUX1	16	13,955	CA1	16	20,989	236.5	−15.9	0.000
NDUX1	17	13,955	CA2	17	22,088	268.1	−15.0	0.000
NDUX1	16	13,955	CAL2	16	20,073	240.9	−16.7	0.000
					Total	3735.6	−209.3