Study of lectins from Photorhabdus luminescens bacterium
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| Year of publication | 2018 |
| Type | Conference abstract |
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| Citation | |
| Description | We present novel lectins from Photorhabdus luminescens with an unusual heptabladed beta-propeller fold. These proteins show very high sequence identity with recently described lectins PLL and PHL from the Photorhabdus genus. Furthermore, all lectins are localized in a row in a bacterial genome. Lectins, a group of proteins capable of binding glycoconjugates specifically and reversibly, are showing their importance in both mutualistic and parasitic interactions between microorganism and hosts. Both of these stages are present in the P. luminescens life cycle. The bacterium is highly pathogenic towards the larval stadium of various insect species and mutualistic with infective juveniles of the nematode Heterorhabditis bacteriophora. For structural and functional characterization of Photorhabdus lectins, the wide range of methods was used, e.g. glycan array, surface plasmon resonance, isothermal titration calorimetry, analytical ultracentrifugation, X-ray crystallography and biological assays performed with human blood and hemolymph (reactive oxygen species production and phenoloxidase activity). Whereas heptabladed beta-propeller fold is common for all studied lectins, the oligomeric state differs from mono- to di-mer. All studied lectins recognize L-fucose and O-methylated disaccharide glucose(1-4)rhamnose, but the fine binding specificities vary. The biological assay shows inhibition of the immune system response in the presence of P. luminescens lectins. Our results indicate these lectins might be involved in P. luminescens pathogenicity towards insect larva. |
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