Abstract
Tectonin is a group of beta-propeller lectin played important roles in innate immunity against pathogens, parasites and predators. Tachypleus plasma lectin 1 (TPL1) derived from Taiwanese Tachypleus tridentatus that has pathogen associated molecular pattern (PAMP) and bacteria binding activities. TPL1 shared 96% amino acid sequence identity with Carcinoscorpius rotundicaudata galactose binding protein (CrGBP) but they have distinct PAMP binding activities. In silico tertiary structure prediction showed that TPL1 and CrGBP revealed beta-propeller structure. In vivo nematotoxicity assay showed that TPL1 has Tectonin property such as inhibiting approximately 60% Caenorhabditis elegans larva development leading abnormally wriggled worm movement. In addition, recombinant TPL1 expressed in Escherichia coli enhanced lipoteichoic acid (LTA), lipopolysaccharide (LPS) and bacteria binding activities, as well as anti-bacterial activity upon addition of calcium ion and galactose. Taken together, recombinant TPL1 was firstly proven in vivo Tectonin property through in silico prediction and in vitro assay. Characterization of carbohydrate binding property of TPL1 may facilitate deciphering antimicrobial mechanism of horseshoe crab and engineering of novel proteins for antimicrobial application.