Purification and characterization of a galactose-specific lectin from the eggs of coho salmon Oncorhynchus kisutch and its interaction with bacterial fish pathogens

Abstract

The yolk of coho salmon Oncorhynchus kisutch eggs contains a lectin which proved capable of binding to Aeromonas salmonicida cells, but showed no such activity with other fish pathogens such as A. hydrophila, Vibrio anguillarum, V. ordalii, or Renibacterium salmoninarum. The interaction between the lectin and A. sahonicida was demonstrated by a test in which the protein was adsorbed onto bacterial cells. Boiling the bacterial cells for 1 h did not alter their ability to adsorb the lect~n. The lectin was purified by affinity chromatography on D-galactose-Sepharose 4B, and was shown by SDS-PAGE to be a 24.5 kDa protein; ~t was heat stable and its binding property was inhibited by D-galactose, D-galactosarnine, and L-rhamnose. The amino acid composition and N-terminal amino acid sequence of the purified lectin were also determined. The amino acid sequence was in places reminiscent of the sequences found in recognition molecules such as antibodies and certain cell receptor sites.