Conformational changes induced by ionic strength and pH in two bovine myelin basic proteins.
The structures of two biologically different myelin proteins, A1 from the central nervous system and P2 from the peripheral nervous system, were investigated. Both proteins were isolated from nerve tissues. Conformational changes in the homogeneous proteins were examined in aqueous solutions by means of circular dichroism measurements. The secondary structures of both proteins proved to be very stable between pH 2.5 and pH 11.7. Unlike the P2 protein, the A1 protein is stable up to pH 13 without detectable conformational changes. The stereochemistry of the polypeptide chains of both proteins is markedly different in the presence of urea. While the value of theta222 for the A1 protein changes linearly with increasing urea concentration, a sigmoidal curve was obtained for the P2 protein. The observed differences in the dichroic properties of the basic myelin proteins A1 and P2 indicate the possibility of further structure - function correlations.
D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D009185:Myelin Proteins; D009994:Osmolar Concentration; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013116:Spinal Cord / Q000032:analysis; D014508:Urea
D009185:Myelin Proteins; D014508:Urea