Basic A1 Protein of the Myelin Membrane

Variable interaction of spin-labeled human myelin basic protein with different acidic lipids

“…once this interaction has occurred there arises the possibility that the protein may be able to interact hydrophobically with the lipid bilayer, depending upon the ability of the protein to present its hydrophobic segments to the hydrocarbon region of the lipid bilayer. An examination of the sequence of the basic protein reveals that segments of hydrophobic and/or uncharged residues (14-21, 26-30, 35-38, 44-47, 60-64, 66-74,85-90, 92-96, 98-104, 108-112, 113-117, 123-129, 146-150, and 163-168) do exist despite the fact that the protein is highly basic (Eylar et al, 1971;Boggs & Moscarello, 1978b). These segments may be regions of the protein which can penetrate into the lipid bilayer or, by distorting the bilayer, interact with the fatty acid chains.…”

“…However, it also possesses 52% hydrophobic or a polar amino acids which are distributed throughout its sequence in regions of four to nine amino acids long (Eylar et al, 1971; Boggs & Moscarello, 1978b). There is abundant evidence that some of these hydrophobic segments may be able to interact with the hydrocarbon region of the bilayer either by penetrating partway into the bilayer or by deforming the bilayer such that hydrophobic contacts at the lipid-water interface can occur.…”

Direct observation by carbon-13 nuclear magnetic resonance of membrane-bound human myelin basic protein

“…Loss of protein spectral intensity on passing from DPPG or DMPA liquid-crystalline to gel states suggested a distribution of environments for MBP lo aid in elucidating the role of myelin basic protein (MBP)1 in organizing the structure of native myelin, the membrane surrounding nerve axons in the central nervous system, it is essential to determine where the protein resides with respect to myelin membrane surfaces and bilayers. The hydrophilic sequence (Eylar et al, 1971) of this abundant myelin protein and its water solubility suggest the character of an extrinsic membrane protein, in which at least portions of its sequence would lie on or near myelin membrane surfaces or interfaces.Critical regions of MBP may be accessible to antibodies or sensitized cells and thus be implicated in triggering the "autoimmune destruction" of myelin. Such a process may be directly or indirectly involved in the onset of multiple sclerosis in humans and in induction of experimental allergic encephalomyelitis (EAE disease) in laboratory animals [for a review, see Maugh (1977)].…”

“…Loss of protein spectral intensity on passing from DPPG or DMPA liquid-crystalline to gel states suggested a distribution of environments for MBP lo aid in elucidating the role of myelin basic protein (MBP)1 in organizing the structure of native myelin, the membrane surrounding nerve axons in the central nervous system, it is essential to determine where the protein resides with respect to myelin membrane surfaces and bilayers. The hydrophilic sequence (Eylar et al, 1971) of this abundant myelin protein and its water solubility suggest the character of an extrinsic membrane protein, in which at least portions of its sequence would lie on or near myelin membrane surfaces or interfaces.…”

Structure and function of the proline-rich region of myelin basic protein

“…Sequence determinations from several sources (Eylar et al, 1971;Carnegie, 1971;Martenson et al, 1971;Martenson, 1981; Small & Carnegie, 1981) have revealed a highly conserved, rarely encountered triproline segment (residues 99-101). Proline residues are known as important structural components of proteins since their conformations are restricted by the carbocyclic pyrrolidine side chain, which is covalently bonded to the protein backbone (Carver & Blout, 1967).…”