System compositions and simulation results.

: Increase in the radius of gyration ( of res. 25–195). Crossings: Water permeation events during 1 . : Osmotic water permeability coefficient. : Single pore osmotic water permeability coefficient for the 3-fold axis. : Number of -helix residues in the N-terminus. : Number of intermolecular hydrogen bonds between pairs of subunits related by 2-, 3- or 5-fold symmetry (disregarding interactions between the N-terminal 11 residues). : RMSd from the crystal structure for 2-, 3- or 5-protein oligomers calculated for the main domain ( of residue 25–195). Average values from the last 0.1 where the ranges indicate the standard error.