Neutron scattering studies on protein dynamics using the human myelin peripheral membrane protein P2

Saara Laulumaa,Petri Kursula,Francesca Natali,B Frick,M M Koza,M Boehm,H Mutka

doi:10.1051/epjconf/20158302010

Abstract

Myelin is a multilayered proteolipid membrane structure surrounding selected axons in the vertebrate nervous system, which allows the rapid saltatory conduction of nerve impulses. Deficits in myelin formation and maintenance may lead to chronic neurological disease. P2 is an abundant myelin protein from peripheral nerves, binding between two apposing lipid bilayers. We studied the dynamics of the human myelin protein P2 and its mutated P38G variant in hydrated powders using elastic incoherent neutron scattering. The local harmonic vibrations at low temperatures were very similar for both samples, but the mutant protein had increased flexibility and softness close to physiological temperatures. The results indicate that a drastic mutation of proline to glycine at a functional site can affect protein dynamics, and in the case of P2, they may explain functional differences between the two proteins.

Highlights

The myelin sheath is an insulating, tightly packed membrane multilayer structure surrounding selected nerve axons
The effect of point mutations on the protein dynamics has been studied before to a lower extend using elastic incoherent scattering (EINS) [19, 20]; the difference in dynamics of wild type and mutated bacteriorhodopsin in purple membrane was not observable [19], whereas in solution, the mutated nonfunctional photosynthetic reaction center was shown to be more dynamic compared to wild type protein complex [20]
We have studied the dynamics of hydrated protein powders using very pure myelin protein P2 samples

Summary

Introduction

The myelin sheath is an insulating, tightly packed membrane multilayer structure surrounding selected nerve axons. It protects and enhances transmission of nervous signals in the central (CNS) and peripheral nervous systems (PNS). Myelin has a unique structure and contains mostly lipids (75 – 80%), very little solvent and myelin-specific proteins at high concentrations. Myelin protein P2 is one of the major components of human peripheral nerve myelin. It is a small 15-kDa fatty acid binding protein (FABP) present mainly in compact myelin constituting up to 15% of the total protein fraction locally [4,5,6]. There is a cocrystallized lipid from E.coli

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Results

Conclusion