Interaction of ganglioside G_M1 and myelin basic protein studied by carbon‐13 and proton nuclear magnetic resonance spectroscopy

Abstract

The interaction of the myelin basic protein (MBP) and the major endogenous ganglioside GM1 in myelin of the central nervous system has been investigated using both 500-MHz 1H and 67.89 MHz 13C NMR. Titration of MBP by GM1 resulted in 13C NMR signal shifts for the I1e and His residues of MBP at a GM1/MBP mole ratio of one or less. The carbohydrate head group of GM1 was also found to be perturbed. 1H NMR results obtained in a similar manner demonstrated the perturbation of His and Phe residues. At a GM1/MBP mole ratio of 0.5, small perturbation of Trp #116 was observed, and at mole ratios of two and beyond significant involvement of Phe residues and methylated Arg #107 was found. Met #167 was more perturbed than Met #20; hence, more extensive interaction of the lipid is occurring with the C-terminus of the protein than with the N-terminus. No resonances from GM1 bound to MBP at mole ratios of up to one appeared in the spectra. However, as the GM1/MBP mole ratio was increased to eight or greater a major conformational change of MBP was detected. An upfield shift of the GM1 midchain methylene resonance was observed for the GM1/MBP complex. This observation provides strong evidence that the state of GM1 interacting with MBP is different from that of GM1 micelles. The number of saturable GM1 binding sites on MBP is estimated to be four. The data also favor a rapid exchange between bound GM1 and GM1 micelles. Interaction of MBP with the oligosaccharide derived from GM1 was found to be weaker than with GM1. Based on our data, a model for the interaction can be proposed: the first GM1 molecule is bound to the protein molecule through its head group and hydrocarbon chains, followed by the formation of a GM1/MBP complex with a concomitant conformational change of MBP as more GM1 is added.

Characterization of a Recombinant Murine 18.5-kDa Myelin Basic Protein

“…To emulate an amphipathic myelin-like environment, CD was performed in the presence of monosialoganglioside G M1 , which binds strongly to MBP and which has been shown to increase its proportion of ordered secondary structure significantly (48,85,86). Here, the same effect was observed for both proteins (Fig.…”

Myelin basic protein—diverse conformational states of an intrinsically unstructured protein and its roles in myelin assembly and multiple sclerosis

“…The classic 18.5 kDa MBP isoform is primarily disordered in aqueous solution, but gains ordered secondary structure (a-helix, b-sheet) in the presence of lipids and detergents, a phenomenon that has been demonstrated countless times (Braun and Radin, 1969;Anthony and Moscarello, 1971;Moscarello et al, 1974;Epand et al, 1974;Liebes et al, 1975;Krigbaum and Hsu, 1975;Chapman and Moore, 1976;Smith, 1977bSmith, , 1985Smith, , 1992Chapman et al, 1978;Martenson, 1978;Littlemore and Ledeen, 1979;Smith, 1979, 1981;Hughes et al, 1982;Mendz et al, 1982Mendz et al, , 1984Mendz et al, , 1988Mendz et al, , 1991Mendz et al, , 1995bMoore, 1982;Moore, 1983, 1985;Smith et al, 1983;Cheifetz et al, 1984;Fraser and Deber, 1984;Ong and Yu, 1984;Riccio et al, 1984Riccio et al, , 1985Stone et al, 1985;Randall and Zand, 1985;Martenson et al, 1985a,b;Boggs et al, 1985a;Gow et al, 1987;Surewicz et al, 1987;Riccio et al, 1990Riccio et al, , 1994Zehetbauer et al, 1991;Hayer-Hartl et al, 1993;Reinl...…”

Homologous sequences in cholera toxin A and B subunits to peptide domains in myelin basic protein

“…The second feature is the closeness of the tryptophan residue to this arginine in MBP. The NMR study [2] also implicated this residue in the binding of the GM~ ganglioside. Although the attachment of azido GTP is reported to occur in MBP at glutamine residue 3 [3], the peptide sequence homology with chol A occurs from residues 8 to 20.…”

“…The isoelectric point is greater than 10.6 [l], it binds GM~ ganglioside [2], GTP [3], and it can be ADPribosylated [4]. The protein and some of its peptides are highly antigenic, and are capable of inducing experimental allergic encephalomyelitis, EAE, in a number of laboratory animals.…”

“…The investigations by Yu and his collaborators [2] showed that the interaction of GMMI ganglioside with MBP occurred in the region of the molecule comprising amino acid residues in proximity to tryptophan 116. The interaction of the single methylated arginine 107 residue with the GM~ molecule was also confirmed.…”