Biophysical characterization of 21.5-kDa myelin basic protein (MBP) and the effects of zinc on its structure

Abstract

Myelin Basic Protein (MBP) is a highly abundant protein in central nervous system (CNS) myelin that has a critical role in its proper formation and functioning. The 21.5-kDa isoform of MBP has been shown to be selectively imported into the nucleus of myelin-producing cells, oligodendrocytes, and may be involved in signaling pathways that affect the formation and recovery of CNS myelin. The first step in understanding potential nuclear binding partners of 21.5-kDa MBP is to characterize the structure of the protein. In this study, circular dichroism and fluorescence spectroscopy were used to analyze the structure of 21.5-kDa rmMBP (recombinant murine MBP) in vitro in the presence and absence of Zn2+, an abundant trace metal in CNS myelin that has been suggested to affect MBP structure. Fluorescence spectroscopy with a probe for hydrophobic protein regions showed that Zn2+ may affect the conformation of 21.5-kDa MBP in aqueous solution. Keywords: myelin basic protein (MBP); intrinsically-disordered protein; circular dichroism; fluoresence spectroscop