Lectins, carbohydrate recognizing proteins, play an important role in various physiological and pathophysiological processes as well as both mutualistic and parasitic interactions between microorganism and hosts [1]. In connection with the last-mentioned process, lectins from pathogenic bacteria can mediate the first step of infection and our goal is to investigate their specificity and suggest potential inhibitors.
Our research is focused on studying lectins from bacterium Photorhabdus, which is known for its complicated life cycle, including mutualism with microscopic nematode and pathogenicity towards insects [2]. Moreover, some species of Photorhabdus are also able to infect humans. In this bacterial genus, two lectins with a seven-bladed beta-propeller fold and a high level of homology were described previously [3,4]. This contribution is focused on the PLL3 lectin, a novel member of the seven-bladed beta-propeller lectin family. PLL3 exhibited the highest affinity toward l-fucose and its derivatives but was also able to interact with O-methylated glycans and other ligands. Unlike the other members of this family, PLL3 was discovered to be a monomer, which might correspond to a weaker avidity effect compared to homologous lectins.
This work was supported by the Czech Science Foundation (project 18-18964S) and by the MEYS of the Czech Republic under the project CEITEC 2020 (LQ1601). CIISB research infrastructure project LM2018127 funded by MEYS CR is also gratefully acknowledged for the financial support of the measurements at the CF Biomolecular Interactions and Crystallization, CF Nanobiotechnology, CF Proteomics at CEITEC (Brno, Czech Republic). We wish to thank the Helmholtz-Zentrum Berlin (Berlin-Adlershof, Germany) for synchrotron radiation beam time.