On the thermal stability of the two dimeric forms of ribonuclease A

The thermal stability of the two dimers of RNase A with N- or C-terminal swapped ends is investigated by means of dissociation kinetics, differential scanning calorimetry, and circular dichroism measurements. The data indicate that the dimer characterized by the swapping of the N-terminal α-helices is less prone to monomerize when compared to the dimer characterized by the swapping of the C-terminal β-strands. This finding is correlated to the structural features of the so-called open interface of the dimeric forms.