Ligand-induced conformation change in folate-binding protein.

摘要: C.d. and fluorescence spectroscopy have been used to investigate the effect of ligand binding on structure stability folate-binding protein (FBP) from cow's whey. The c.d. spectrum unligated FBP predicts following secondary structure: 22% helix, 25% antiparallel beta-strand, 5% parallel 17% turn 31% random-coil structure. Folate results in significant changes spectrum. Analysis shows a 10% decrease beta-strand as result binding. also leads strong quenching tryptophan fluorescence. magnitude quench is proportional guanidinium chloride-induced unfolding shown be multistate process. Detection by lead non-identical transitions. Modelling studies are consistent with existence stable folding intermediate. Ligand increases apparent molecule. Simultaneous detection indicate that increased derived ligand-induced aggregation FBP.