Structural and dynamical properties of reconstituted myelin sheaths in the presence of myelin proteins MBP and P2 studied by neutron scattering.

The myelin sheath is a tightly packed, multilayered membrane structure wrapped around selected nerve axons in the central and the peripheral nervous system. Because of its electrical insulation of the axons, which allows fast, saltatory nerve impulse conduction, myelin is crucial for the proper functioning of the vertebrate nervous system. A subset of myelin-specific proteins is well-defined, but their influence on membrane dynamics, i.e. myelin stability, has not yet been explored in detail. We investigated the structure and the dynamics of reconstituted myelin membranes on a pico- to nanosecond timescale, influenced by myelin basic protein (MBP) and myelin protein 2 (P2), using neutron diffraction and quasi-elastic neutron scattering. A model for the scattering function describing molecular lipid motions is suggested. Although dynamical properties are not affected significantly by MBP and P2 proteins, they act in a highly synergistic manner influencing the membrane structure.