The modelling of the CC-Hex*-L24E system at different pH conditions was done by assigning fixed protonation states to the Glu residues; at low pH, all Glu residues were protonated, whereas at high pH all the Glu residues were deprotonated. Experimental data suggest CC-Hex*-L24E forms a parallel hexamer at pH 2-6.5 and an antiparallel tetramer at pH >7.