F-type lectin from serum of the Antarctic teleost fish Trematomus bernacchii (Boulenger, 1902): Purification, structural characterization, and bacterial agglutinating activity

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
• Main Authors: Dara M., Giulianini P. G., Manfrin C., Parisi M. G., Parrinello D., La Corte C., Vasta G. R., Cammarata M.
• Other Authors: Dara, M., Giulianini, P. G., Manfrin, C., Parisi, M. G., Parrinello, D., La Corte, C., Vasta, G. R., Cammarata, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Antarctic fish; Bacterial agglutination; F-type lectin; Lectin; Trematomus bernacchii; Amino Acid Sequence; Animal; Antarctic Region; Bacteria; Base Sequence; Fucose; Perciforme; Phylogeny; Antarctic; The Antarctic; Antarc*
• Online Access: http://hdl.handle.net/11368/3028959; https://doi.org/10.1016/j.cbpb.2021.110633; https://www.sciencedirect.com/science/article/pii/S1096495921000725

The increasing availability of sequenced genomes has enabled a deeper understanding of the complexity of fish lectin repertoires involved in early development and immune recognition. The teleost fucose-type lectin (FTL) family includes proteins that preferentially bind fucose and display tandemly arrayed carbohydrate-recognition domains (CRDs) or are found in mosaic combinations with other domains. They function as opsonins, promoting phagocytosis and the clearance of microbial pathogens. The Antarctic fish Trematomus bernacchii is a Perciforme living at extremely low temperatures (−1.68 °C) which is considered a model for studying adaptability to the variability of environmental waters. Here, we isolated a Ca++-independent fucose-binding protein from the serum of T. bernacchii by affinity chromatography with apparent molecular weights of 32 and 30 kDa under reducing and non-reducing conditions, respectively. We have characterized its carbohydrate binding properties, thermal stability and potential ability to recognize bacterial pathogens. In western blot analysis, the protein showed intense cross-reactivity with antibodies specific for a sea bass (Dicentrarchus labrax) fucose-binding lectin. In addition, its molecular and structural aspects, showing that it contains two CRD-FTLs confirmed that T. bernacchii FTL (TbFTL) is a bona fide member of the FTL family, with binding activity at low temperatures and the ability to agglutinate bacteria, thereby suggesting it participates in host-pathogen interactions in low temperature environments.