’N-Terminal Amino Acid Analysis of Hemagglutinin Molecules from Duck and Equine Influenza Viruses Previously Implicated as Progenitors of the Hong Kong Strain of Human Influenza
The hemagglutinin molecules from a number of strains of influenza virus, including those of the Asian (H2N2) series, have been found to possess N-terminal aspartic acid (or asparagine) at the N-terminus of the large polypeptide (HA1). The only virus strains found so far which do not possess N-terminal aspartic acid on the hemagglutinin are those of the Hong Kong (H3N2) series, where the N-terminus seems to be blocked.
We have found that the hemagglutinin molecules of equine-2 (Heq2Neq2) and duck/Ukraine (Hav7Neq2) viruses also lack N-terminal aspartic acid. This finding is consistant with the idea that the hemagglutinin molecules of Hong Kong influenza virus were derived, by genetic recombination, from a virus related to equine-2 and duck/Ukraine viruses and that they did not arise by mutation of an Asian (H2N2) influenza virus.
KeywordsInfluenza Virus Guanidine Hydrochloride Blue Filter Precursor Polypeptide Equine Influenza Virus
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