Structural properties of staphylococcal nuclease in oligomeric A-forms.

Association affects the structural properties of different partially folded conformations of staphylococcal nuclease induced by anions of different nature. It is shown that oligomerization induces new structural levels in non-native A-forms. A close structural similarity between the monomeric A2 and the dimeric (A1)2 forms as well as between the monomeric A3 and oligomeric [(A1)2]M and [A2]M forms is established. This suggests that association of a protein molecule in partially folded conformations can be an additional structure forming factor.