Conformational specificity of trigger factor for the folding intermediates of alpha-lactalbumin.

To understand the structural features of polypeptides recognized by trigger factor, a number of conformational derivatives of alphaLA were prepared and their effects on the trigger factor assisted refolding of GAPDH were investigated. It was found that the conformers of alphaLA that efficiently reduce the trigger factor assisted reactivation of guanidine-denatured GAPDH by competitively binding with trigger factor are those derivatives that have loose structure. This suggests that trigger factor binds mainly to intermediates formed early during folding of GAPDH.