Bovine P2 Protein: Sequence at the NH2‐Terminal of the Protein

Abstract

Sequence data from key fragments of the P2 protein established the order of CNBr peptides in the structure of the protein and the primary structure for approximately 1/2 of the molecule. Data were obtained from the 3 tryptic peptides of blocked NH2-terminal CNBr peptide (CN3), the large CNBr peptide of P2 protein (CN1) and a fragment obtained from P2 by cleavage at tryptophan with 2-(2-nitrophenylsulfenyl)-3-methyl-3''-bromoindolenine. This last fragment contained an overlapping sequence that proved the juxtaposition of CN1 and CN3 in P2 protein. The P2 structure is composed of CNBr peptides in the order: CN3-CN1-CN2(Val)-CN2(Lys). A comparison was made between the partial sequence of P2 protein and the equivalent portion of the structure of bovine myelin basic protein. The structures of these 2 proteins were distinctly different although similarities are found. P2 is responsible for induction of experimental allergic neuritis, an animal model for human Guillain-Barre syndrome.