Conformation of myelin basic protein bound to phosphatidylinositol membrane characterized by vacuum‐ultraviolet circular‐dichroism spectroscopy and molecular‐dynamics simulations

• DOI: 10.1002/prot.26146
• Publication Date: 2021-05-17T05:53:55Z
• Authors: Munehiro Kumashiro; Yudai Izumi; Koichi Matsuo
• Keywords: Helix (gastropod); Membrane structure

The 18.5-kDa isoform of myelin basic protein (MBP) interacts with the membrane surface sheath to construct its compact multilamellar structure. This study characterized conformation MBP in by measuring vacuum-ultraviolet circular-dichroism (VUVCD) spectra bilayer liposome comprising following essential lipid constituents sheath: phosphatidylinositol (PI), phosphatidylinositol-4-phosphate (PIP), and phosphatidylinositol-4,5-bisphosphate (PIP2). exhibited characteristic peaks helix structure presence PI liposome, intensity increased markedly PIP PIP2 liposomes show an isodichroic point. suggests that amount membrane-bound enhanced due number negative net charges on surfaces. Secondary-structure analysis revealed comprised approximately 40% contents eight segments. Molecular-dynamics (MD) simulations segments were conducted for 250 ns membrane, which predicted two amphiphilic three nonamphiphilic helices as membrane-interaction sites. Further distances amino-acid residues each segment from phosphate group suggested interact electrostatically, while ones invade inside produce electrostatic hydrophobic interactions. These results can via under control a delicate balance between