Photorhabdus laumondii is a well-known bacterium with a complex life cycle involving mutualism with nematodes of the genus Heterorhabditis and pathogenicity towards insect hosts. It provides an excellent model for studying the diverse roles of lectins, saccharide-binding proteins, in both symbiosis and pathogenicity. This study focuses on the seven-bladed β-propeller lectins of P. laumondii (PLLs), examining their biochemical properties (structure and saccharide specificity) and biological functions (gene expression, interactions with the nematode symbiont, and the host immune system response). Structural analyses revealed diverse oligomeric states among PLLs and a unique organisation of binding sites not described outside the PLL lectin family. Lectins exhibited high specificity for fucosylated and O-methylated saccharides with a significant avidity effect for multivalent ligands. Gene expression analysis across bacterial growth phases revealed that PLLs are predominantly expressed during the exponential phase. Interaction studies with the host immune system demonstrated that PLL5 uniquely induced melanisation in Galleria mellonella hemolymph. Furthermore, PLL2, PLL3, and PLL5 interfered with reactive oxygen species production in human blood cells, indicating their potential role in modulating host immune responses. Biofilm formation assays and binding studies with nematode life stages showed no significant involvement of PLLs in nematode colonization. Our findings highlight the primary role of PLLs in Photorhabdus pathogenicity rather than in symbiosis and offer valuable insight into the fascinating dynamics within the Photorhabdus-nematode-insect triparted system.

• Klíčová slova
• Photorhabdus, glycan array, lectin, nematode, structure-function study,
• MeSH
• bakteriální proteiny * chemie   metabolismus   genetika   MeSH
• hlístice * mikrobiologie   MeSH
• lektiny * chemie   metabolismus   genetika   MeSH
• lidé MeSH
• Photorhabdus * metabolismus   chemie   genetika   MeSH
• symbióza MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny * MeSH
• lektiny * MeSH

Series of multivalent α-l-fucoside containing glycoclusters and variously decorated l-fucosides were synthesized to find potential inhibitors of fucose-specific lectins and study the structure-binding affinity relationships. Tri- and tetravalent fucoclusters were built using copper-mediated azide-alkyne click chemistry. Series of fucoside monomers and dimers were synthesized using various methods, namely glycosylation, an azide-alkyne click reaction, photoinduced thiol-en addition, and sulfation. The interactions between compounds with six fucolectins of bacterial or fungal origin were tested using a hemagglutination inhibition assay. As a result, a tetravalent, α-l-fucose presenting glycocluster showed to be a ligand that was orders of magnitude better than a simple monosaccharide for tested lectins in most cases, which can nominate it as a universal ligand for studied lectins. This compound was also able to inhibit the adhesion of Pseudomonas aeruginosa cells to human epithelial bronchial cells. A trivalent fucocluster with a protected amine functional group also seems to be a promising candidate for designing glycoconjugates and chimeras.

• Klíčová slova
• cystic fibrosis, glycoclusters, hemagglutination, l-fucosides, lectins, multivalency,
• MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• fukosa chemie   metabolismus   MeSH
• fungální proteiny chemie   metabolismus   MeSH
• hemaglutinace MeSH
• lektiny chemie   metabolismus   MeSH
• lidé MeSH
• testy inhibice hemaglutinace MeSH
• vazba proteinů MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• fucose-binding lectin MeSH Prohlížeč
• fukosa MeSH
• fungální proteiny MeSH
• lektiny MeSH

Protein-carbohydrate interactions are very often mediated by the stacking CH-π interactions involving the side chains of aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr) or phenylalanine (Phe). Especially suitable for stacking is the Trp residue. Analysis of the PDB database shows Trp stacking for 265 carbohydrate or carbohydrate like ligands in 5 208 Trp containing motives. An appropriate model system to study such an interaction is the AAL lectin family where the stacking interactions play a crucial role and are thought to be a driving force for carbohydrate binding. In this study we present data showing a novel finding in the stacking interaction of the AAL Trp side chain with the carbohydrate. High resolution X-ray structure of the AAL lectin from Aleuria aurantia with α-methyl-l-fucoside ligand shows two possible Trp side chain conformations with the same occupation in electron density. The in silico data shows that the conformation of the Trp side chain does not influence the interaction energy despite the fact that each conformation creates interactions with different carbohydrate CH groups. Moreover, the PDB data search shows that the conformations are almost equally distributed across all Trp-carbohydrate complexes, which would suggest no substantial preference for one conformation over another.

• MeSH
• databáze proteinů MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• lektiny chemie   metabolismus   MeSH
• metabolismus sacharidů * MeSH
• tryptofan chemie   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• lectin, Aleuria aurantia MeSH Prohlížeč
• lektiny MeSH
• tryptofan 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

The Aleuria aurantia lectin (AAL) derived from orange peel fungus contains five fucose-binding sites that recognizes fucose bound in α-1,2, α-1,3, α-1,4, and α-1,6 linkages to N-acetylglucosamine and galactose. Recently, we have created several recombinant AAL (rAAL) proteins that had altered binding affinity to fucose linkages. In this report, we further characterize the binding specificity of one of the mutated lectins, N224Q lectin. This lectin was characterized by lectin Western blotting, surface plasmon resonance, and glycan microarray and shown to have increased binding to fucosylated glycan. Subsequently, we used this lectin to identify secreted fucosylated glycoproteins from a fetal hepatic cell line. Proteomic analysis revealed several glycoproteins secreted by the fetal cell line that were bound by N224Q lectin. These findings were confirmed by subsequent proteomic analysis of human serum from control patients or patients with hepatocellular carcinoma. These represent candidate oncofetal markers for liver cancer.

• Klíčová slova
• Aleuria aurantia lectin, Biomarker, Glycoproteomics, Glycosylation, Hepatocellular carcinoma, Liver cancer,
• MeSH
• Ascomycota chemie   MeSH
• buněčné linie MeSH
• fukosa analýza   metabolismus   MeSH
• glykoproteiny analýza   metabolismus   MeSH
• hepatocelulární karcinom diagnóza   metabolismus   MeSH
• hepatocyty metabolismus   patologie   MeSH
• játra metabolismus   patologie   MeSH
• kultivované buňky MeSH
• lektiny chemie   metabolismus   MeSH
• lidé MeSH
• nádorové biomarkery analýza   metabolismus   MeSH
• nádory jater diagnóza   metabolismus   MeSH
• polysacharidy chemie   metabolismus   MeSH
• proteomika MeSH
• rekombinantní proteiny chemie   metabolismus   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• fukosa MeSH
• glykoproteiny MeSH
• lectin, Aleuria aurantia MeSH Prohlížeč
• lektiny MeSH
• nádorové biomarkery MeSH
• polysacharidy MeSH
• rekombinantní proteiny MeSH

Photorhabdus luminescens is known for its symbiosis with the entomopathogenic nematode Heterorhabditis bacteriophora and its pathogenicity toward insect larvae. A hypothetical protein from P. luminescens was identified, purified from the native source, and characterized as an l-fucose-binding lectin, named P. luminescens lectin (PLL). Glycan array and biochemical characterization data revealed PLL to be specific toward l-fucose and the disaccharide glycan 3,6-O-Me2-Glcβ1-4(2,3-O-Me2)Rhaα-O-(p-C6H4)-OCH2CH2NH2 PLL was discovered to be a homotetramer with an intersubunit disulfide bridge. The crystal structures of native and recombinant PLL revealed a seven-bladed β-propeller fold creating seven putative fucose-binding sites per monomer. The crystal structure of the recombinant PLL·l-fucose complex confirmed that at least three sites were fucose-binding. Moreover, the crystal structures indicated that some of the other sites are masked either by the tetrameric nature of the lectin or by incorporation of the C terminus of the lectin into one of these sites. PLL exhibited an ability to bind to insect hemocytes and the cuticular surface of a nematode, H. bacteriophora.

• Klíčová slova
• Galleria mellonella, Photorhabdus luminescens, bacterial pathogenesis, crystal structure, hemocytes from insect larvae, host/pathogen interaction, lectin, structural biology,
• MeSH
• bakteriální proteiny chemie   izolace a purifikace   MeSH
• fukosa chemie   MeSH
• krystalografie rentgenová MeSH
• kvarterní struktura proteinů MeSH
• lektiny chemie   izolace a purifikace   MeSH
• Photorhabdus chemie   MeSH
• proteinové domény MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bakteriální proteiny MeSH
• fukosa MeSH
• lektiny MeSH

The immune mechanisms that recognize inhaled Aspergillus fumigatus conidia to promote their elimination from the lungs are incompletely understood. FleA is a lectin expressed by Aspergillus fumigatus that has twelve binding sites for fucosylated structures that are abundant in the glycan coats of multiple plant and animal proteins. The role of FleA is unknown: it could bind fucose in decomposed plant matter to allow Aspergillus fumigatus to thrive in soil, or it may be a virulence factor that binds fucose in lung glycoproteins to cause Aspergillus fumigatus pneumonia. Our studies show that FleA protein and Aspergillus fumigatus conidia bind avidly to purified lung mucin glycoproteins in a fucose-dependent manner. In addition, FleA binds strongly to macrophage cell surface proteins, and macrophages bind and phagocytose fleA-deficient (∆fleA) conidia much less efficiently than wild type (WT) conidia. Furthermore, a potent fucopyranoside glycomimetic inhibitor of FleA inhibits binding and phagocytosis of WT conidia by macrophages, confirming the specific role of fucose binding in macrophage recognition of WT conidia. Finally, mice infected with ΔfleA conidia had more severe pneumonia and invasive aspergillosis than mice infected with WT conidia. These findings demonstrate that FleA is not a virulence factor for Aspergillus fumigatus. Instead, host recognition of FleA is a critical step in mechanisms of mucin binding, mucociliary clearance, and macrophage killing that prevent Aspergillus fumigatus pneumonia.

• MeSH
• Aspergillus fumigatus imunologie   patogenita   MeSH
• dospělí MeSH
• fluorescenční protilátková technika MeSH
• fukosa metabolismus   MeSH
• fungální proteiny imunologie   metabolismus   MeSH
• lektiny imunologie   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• makrofágy imunologie   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• muciny imunologie   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• plicní aspergilóza imunologie   metabolismus   MeSH
• průtoková cytometrie MeSH
• slizniční imunita imunologie   MeSH
• spory hub imunologie   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• fucose-binding lectin MeSH Prohlížeč
• fukosa MeSH
• fungální proteiny MeSH
• lektiny MeSH
• muciny MeSH

Aspergillus fumigatus is an important allergen and opportunistic pathogen. Similarly to many other pathogens, it is able to produce lectins that may be involved in the host-pathogen interaction. We focused on the lectin AFL, which was prepared in recombinant form and characterized. Its binding properties were studied using hemagglutination and glycan array analysis. We determined the specificity of the lectin towards l-fucose and fucosylated oligosaccharides, including α1-6 linked core-fucose, which is an important marker for cancerogenesis. Other biologically relevant saccharides such as sialic acid, d-mannose or d-galactose were not bound. Blood group epitopes of the ABH and Lewis systems were recognized, Le(Y) being the preferred ligand among others. To provide a correlation between the observed functional characteristics and structural basis, AFL was crystallized in a complex with methyl-α,L-selenofucoside and its structure was solved using the SAD method. Six binding sites, each with different compositions, were identified per monomer and significant differences from the homologous AAL lectin were found. Structure-derived peptides were utilized to prepare anti-AFL polyclonal antibodies, which suggested the presence of AFL on the Aspergillus' conidia, confirming its expression in vivo. Stimulation of human bronchial cells by AFL led to IL-8 production in a dose-dependent manner. AFL thus probably contributes to the inflammatory response observed upon the exposure of a patient to A. fumigatus. The combination of affinity to human epithelial epitopes, production by conidia and pro-inflammatory activity is remarkable and shows that AFL might be an important virulence factor involved in an early stage of A. fumigatus infection.

• MeSH
• Aspergillus fumigatus chemie   MeSH
• aspergilóza imunologie   MeSH
• bronchy cytologie   mikrobiologie   MeSH
• epitopy chemie   MeSH
• faktory virulence chemie   MeSH
• fukosa chemie   MeSH
• galaktosa chemie   MeSH
• genom fungální MeSH
• hemaglutinace MeSH
• interakce hostitele a patogenu MeSH
• interleukin-8 metabolismus   MeSH
• kyselina N-acetylneuraminová chemie   MeSH
• lektiny chemie   MeSH
• lidé MeSH
• mannosa chemie   MeSH
• molekulární sekvence - údaje MeSH
• oligosacharidy chemie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• sekvenční seřazení MeSH
• spory hub chemie   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• epitopy MeSH
• faktory virulence MeSH
• fucose-binding lectin MeSH Prohlížeč
• fukosa MeSH
• galaktosa MeSH
• interleukin-8 MeSH
• kyselina N-acetylneuraminová MeSH
• lektiny MeSH
• mannosa MeSH
• oligosacharidy MeSH