The New Member of OAAH-Family Lectins from the Cultivated Red Alga Eucheuma denticulatum in Vietnam

Abstract

The red alga Eucheuma denticulatum is an economically important food species extensively cultivated in Vietnam. In this study, complementary DNA (cDNA) cloning based on the rapid amplification of cDNA ends (RACE) methods elucidated the full-length sequence of a new lectin-like protein (named EDL)from this alga. The cDNA cloning of thelectin-like protein encoded a polypeptide of 268 amino acids including an initiating methionine. The deduced amino acid sequence of lectin-like protein composed of four tandem repeated domains of about 67 amino acids and sharing 45% sequence identity.The primary structure of the lectin-like protein, EDL, highly resemble with those of the anti-virus and anti-cancer high-mannose N-glycan specific lectins in lower organisms including Oscillatoria agardhii NIES-240 (OAA) from cyanobacterium, Burkholderia oklahomensis EO147 (BOA), Myxococcus xanthus (MBHA) and Pseudomonas fluorescens Pf0-1 (PFL) from proteobacteria, Eucheuma serra (ESA-2), Eucheuma denticulatum (EDA-2), Kappaphycus striatus (KSA-1 and KSA-2), Kappaphycus alvarezii (KAA-1 and KAA-2) and Solieria filiformis (SfL-1 and SfL-2) from carrageenophyte red algae. The high resemblance in structure with anti-virus and anti-cancer lectins suggests that the cultivated red alga E. denticulatum could also be a good source of functional protein (lectin) for application.