INTERACTION OF NATIVE AND PARTIALLY FOLDED CONFORMATIONS OF ALPHA-LACTALBUMIN WITH LIPID BILAYERS - CHARACTERIZATION OF 2 MEMBRANE-BOUND STATES

alpha-lactalbumin (alpha LA) can adopt two different membrane-bound st ates depending on the physical properties of the lipid bilayer, namely adsorbed and inserted, The latter, but not the adsorbed state, is abl e to disrupt the permeability barrier of the bilayer, The structure of both states is strongly affected by the conformational properties of the alpha LA conformer considered: as protein flexibility increases th e helical content of the membrane-bound conformation decreases, especi ally in the adsorbed form, Moreover, the adsorbed and the inserted sta tes of those conformers containing 3 or 4 disulfides can interconvert in response to changes in the physical properties of the host membrane .