The Photorhabdus species is a Gram-negative bacteria of the family Morganellaceae that is known for its mutualistic relationship with Heterorhabditis nematodes and pathogenicity toward insects. This study is focused on the characterization of the recombinant lectin PLL3 with an origin in P. laumondii subsp. laumondii. PLL3 belongs to the PLL family of lectins with a seven-bladed β-propeller fold. The binding properties of PLL3 were tested by hemagglutination assay, glycan array, isothermal titration calorimetry, and surface plasmon resonance, and its structure was determined by X-ray crystallography. Obtained data revealed that PLL3 binds similar carbohydrates to those that the other PLL family members bind, with some differences in the binding properties. 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. Based on the similarity to the related lectins and their proposed biological function, PLL3 might accompany them during the interaction of P. laumondii with both the nematode partner and the insect host.

• Keywords
• O-methylated saccharides, Photorhabdus, l-fucose, lectin,
• MeSH
• Bacterial Proteins chemistry   genetics   metabolism   MeSH
• Fructose metabolism   MeSH
• Calorimetry MeSH
• Crystallography, X-Ray MeSH
• Lectins chemistry   genetics   metabolism   MeSH
• Photorhabdus metabolism   MeSH
• Surface Plasmon Resonance MeSH
• Recombinant Proteins chemistry   metabolism   MeSH
• Protein Structure, Secondary MeSH
• Binding Sites MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• Fructose MeSH
• Lectins MeSH
• Recombinant Proteins MeSH

A recently described bangle lectin (PHL) from the bacterium Photorhabdus asymbiotica was identified as a mainly fucose-binding protein that could play an important role in the host-pathogen interaction and in the modulation of host immune response. Structural studies showed that PHL is a homo-dimer that contains up to seven L-fucose-specific binding sites per monomer. For these reasons, potential ligands of the PHL lectin: α-L-fucopyranosyl-containing mono-, di-, tetra-, hexa- and dodecavalent ligands were tested. Two types of polyvalent structures were investigated - calix[4]arenes and dendrimers. The shared feature of all these structures was a C-glycosidic bond instead of the more common but physiologically unstable O-glycosidic bond. The inhibition potential of the tested structures was assessed using different techniques - hemagglutination, surface plasmon resonance, isothermal titration calorimetry, and cell cross-linking. All the ligands proved to be better than free L-fucose. The most active hexavalent dendrimer exhibited affinity three orders of magnitude higher than that of standard L-fucose. To determine the binding mode of some ligands, crystal complex PHL/fucosides 2 - 4 were prepared and studied using X-ray crystallography. The electron density in complexes proved the presence of the compounds in 6 out of 7 fucose-binding sites.

• MeSH
• Anti-Bacterial Agents chemistry   pharmacology   therapeutic use   MeSH
• Bacterial Infections drug therapy   microbiology   MeSH
• Bacterial Proteins antagonists & inhibitors   chemistry   isolation & purification   metabolism   MeSH
• Dendrimers chemistry   pharmacology   therapeutic use   MeSH
• Erythrocytes MeSH
• Fucose analogs & derivatives   pharmacology   therapeutic use   MeSH
• Hemagglutination drug effects   MeSH
• Host-Pathogen Interactions drug effects   MeSH
• Crystallography, X-Ray MeSH
• Lectins antagonists & inhibitors   chemistry   isolation & purification   metabolism   MeSH
• Humans MeSH
• Ligands MeSH
• Models, Molecular MeSH
• Photorhabdus metabolism   MeSH
• Surface Plasmon Resonance MeSH
• Recombinant Proteins chemistry   isolation & purification   metabolism   MeSH
• Binding Sites MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacterial Proteins MeSH
• Dendrimers MeSH
• fucose-binding lectin MeSH Browser
• Fucose MeSH
• Lectins MeSH
• Ligands MeSH
• Recombinant Proteins MeSH