Molecular characterization of a lectin, BPL-4, from the marine green alga Bryopsis plumosa (Chlorophyta)

A novel lectin specific to N-acetyl-D-galactosamine as well as N-acetyl-D-glucosamine was isolated from Bryopsis plumosaand named as BPL-4. Sodium dodecyl sulfate polyacrylamide gel electrophorese (SDS-PAGE) and matrix-assistedlaser desorption / ionization-time of flight (MALDI-TOF) mass spectrometry data showed that this lectin was a monomericprotein with molecular weight 12.9 kDa. The N-terminal amino acid sequences of the lectin were determined byEdman degradation and the full cDNA sequence encoding this lectin was obtained using the degenerate primers designedfrom the amino acid sequence. The size of the cDNA was 414 bp containing single open reading frame (ORF) encodingthe lectin precursor. The homology analysis showed that this lectin might belong to H lectin group. BPL-4 showedhigh sequence similarity (60.6%) to BPL-3, which is a previously reported lectin from the same species. The comparativeanalysis on the lectin’s primary structure showed two conserved domains including one possible active domain of Hlectin group.