2Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia
Received August 25, 1997
Structural properties of an equilibrium intermediate formed upon urea-induced unfolding of more ordered staphylococcal nuclease A-forms (A2 and A3) are studied. The effect of association on the structural properties and conformational stability of this unfolding intermediate is also considered. A close structural similarity (including tendency for association) is shown between this intermediate and the least ordered A1-form, induced in the acid-unfolded nuclease by moderate sulfate or chloride concentrations.
KEY WORDS: staphylococcal nuclease, partially-folded states, anion-induced forms, association, equilibrium unfolding intermediate