Structural Dynamics of Myelin Basic Protein in the Assembly of a Model Membrane

Abstract

The encephalitogenic myelin basic protein (MBP), with a MW of 18.4 KDa protein, is the smallest of the CNS myelin proteins, and accounts for about 30% of their total content (Boggs et al., 1982). MBP, when extracted with organic solvents, is soluble in water and has been extensively studied because of its ability to induce inflammatory demyelination (Kies et al., 1965). Recently Riccio et al. (1986) reported EM evidence that MBP, extracted with endogenous lipids employing the detergent CTAB, was able to induce lysolecithin to undergo a structural transition from micelles into multilamellar vesicles. On the other hand lipid-free MBP interacted with lysolecithin but was not able to induce such a transition. The aim of this work is to study the ability of lipids to modulate protein conformation and of a protein such as MBP to influence lipid supramolecular organization. Static and time resolved fluorescence of the single tryptophan residue of MBP and CD measurements are presented that illustrate interesting details of the molecular dynamics involved in lipid protein interactions.