Amino acid sequence of cyanogen bromide fragment CN2 from Hong Kong influenza haemagglutinin heavy chain.

The amino acid sequence of cyanogen bromide peptide CN2 from the heavy chain (HA1) of the haemagglutinin of the Hong Kong variant A/Memphis/102/72 has been obtained by direct, automated sequence analysis on the whole fragment and by manual dansyl-Edman degradation of tryptic, peptic and chymotryptic peptides. It was found to contain 92 amino acid residues, including a large, insoluble, tryptic core peptide (residues 62-87). It did not contain any half-cystine residues or carbohydrate. The determination of its structure was complicated by the presence of an Asn-Ile bond at positions 48-49 which was readily cleaved by both trypsin and chymotrypsin.