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.

• Klíčová slova
• O-methylated saccharides, Photorhabdus, l-fucose, lectin,
• MeSH
• bakteriální proteiny chemie   genetika   metabolismus   MeSH
• fruktosa metabolismus   MeSH
• kalorimetrie MeSH
• krystalografie rentgenová MeSH
• lektiny chemie   genetika   metabolismus   MeSH
• Photorhabdus metabolismus   MeSH
• povrchová plasmonová rezonance MeSH
• rekombinantní proteiny chemie   metabolismus   MeSH
• sekundární struktura proteinů MeSH
• vazebná místa MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• fruktosa MeSH
• lektiny MeSH
• rekombinantní proteiny 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
• antibakteriální látky chemie   farmakologie   terapeutické užití   MeSH
• bakteriální infekce farmakoterapie   mikrobiologie   MeSH
• bakteriální proteiny antagonisté a inhibitory   chemie   izolace a purifikace   metabolismus   MeSH
• dendrimery chemie   farmakologie   terapeutické užití   MeSH
• erytrocyty MeSH
• fukosa analogy a deriváty   farmakologie   terapeutické užití   MeSH
• hemaglutinace účinky léků   MeSH
• interakce hostitele a patogenu účinky léků   MeSH
• krystalografie rentgenová MeSH
• lektiny antagonisté a inhibitory   chemie   izolace a purifikace   metabolismus   MeSH
• lidé MeSH
• ligandy MeSH
• molekulární modely MeSH
• Photorhabdus metabolismus   MeSH
• povrchová plasmonová rezonance MeSH
• rekombinantní proteiny chemie   izolace a purifikace   metabolismus   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• bakteriální proteiny MeSH
• dendrimery MeSH
• fucose-binding lectin MeSH Prohlížeč
• fukosa MeSH
• lektiny MeSH
• ligandy MeSH
• rekombinantní proteiny MeSH

Photorhabdus asymbiotica is one of the three recognized species of the Photorhabdus genus, which consists of gram-negative bioluminescent bacteria belonging to the family Morganellaceae. These bacteria live in a symbiotic relationship with nematodes from the genus Heterorhabditis, together forming a complex that is highly pathogenic for insects. Unlike other Photorhabdus species, which are strictly entomopathogenic, P. asymbiotica is unique in its ability to act as an emerging human pathogen. Analysis of the P. asymbiotica genome identified a novel fucose-binding lectin designated PHL with a strong sequence similarity to the recently described P. luminescens lectin PLL. Recombinant PHL exhibited high affinity for fucosylated carbohydrates and the unusual disaccharide 3,6-O-Me2-Glcβ1-4(2,3-O-Me2)Rhaα-O-(p-C6H4)-OCH2CH2NH2 from Mycobacterium leprae. Based on its crystal structure, PHL forms a seven-bladed β-propeller assembling into a homo-dimer with an inter-subunit disulfide bridge. Investigating complexes with different ligands revealed the existence of two sets of binding sites per monomer-the first type prefers l-fucose and its derivatives, whereas the second type can bind d-galactose. Based on the sequence analysis, PHL could contain up to twelve binding sites per monomer. PHL was shown to interact with all types of red blood cells and insect haemocytes. Interestingly, PHL inhibited the production of reactive oxygen species induced by zymosan A in human blood and antimicrobial activity both in human blood, serum and insect haemolymph. Concurrently, PHL increased the constitutive level of oxidants in the blood and induced melanisation in haemolymph. Our results suggest that PHL might play a crucial role in the interaction of P. asymbiotica with both human and insect hosts.

• MeSH
• bakteriální proteiny genetika   imunologie   MeSH
• interakce hostitele a patogenu imunologie   MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• lektiny chemie   genetika   imunologie   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• Photorhabdus genetika   imunologie   MeSH
• povrchová plasmonová rezonance MeSH
• sekvence nukleotidů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• fucose-binding lectin MeSH Prohlížeč
• lektiny MeSH