N.M.R. Studies of Myelin Basic Protein. III. Interactions of the Protein with Lipid Micelles by 1H and 31P N.M.R.

Abstract

The interactions of bovine myelin basic protein with bovine brain GM1 ganglioside and with lysophosphatidylcholine have been followed by 1H and 31P N.M.R. The effect of the binding of lipid on the protein spectrum could be followed in methyl peaks due to methionine and NG-methylarginine and in peaks from aromatic side chains. Both lipids caused broadening of methyl resonances from methionine-20, the unique NG-methylarginine and phenylalanines. The N.M.R. spectral changes on interaction of peptides derived from N-terminal and C-terminal halves of the protein with lysolecithin indicated that the lipid binding was associated with conformational changes involving the central regions of the polypeptide chain and the methylarginine residue. The 31P spectra suggest that the average phosphate group in lysophosphatidylcholine becomes more mobile as a result of binding of basic protein to the lipid micelle.