Comparative analysis of two bacterial binding lectins

Tachypleus plasma lectin 2 (TPL2) derived from Taiwanese Tachypleus tridentatus recognizes spceific bacteria and shows a 76% sequence identity with another bacteria binding lectin, Tachylectin-3 (TL-3), derived from Japanese T. Tridentatus. Neither secondary nor tertiary structure of these two bacteria binding lectins has ever been solved yet. In this study TPL2 and TL-3 structures were predicted to possess two separate domains by Phyre database. Several ligand binding sites containing hydrophilic aromatic residues were predicted by feature-incorporated alignment (FIA) and molecular docking, and selective ligand binding residues in TPL2 were verified by in vitro assays. Interestingly, TPL2 and TL-3 showed differential ligand binding preference and activities, which might be correlated with minor differences in their structural and functional features.