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The Plasmodium falciparum blood stages acquire factor H family proteins to evade destruction by human complement
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Che J. Ngwa Meike Kiesow Rainer Fischer Peter F. Zipfel Christine Skerka Gabriele Pradel 《Cellular microbiology》2016,18(4):573-590
The acquisition of regulatory proteins is a means of blood‐borne pathogens to avoid destruction by the human complement. We recently showed that the gametes of the human malaria parasite Plasmodium falciparum bind factor H (FH) from the blood meal of the mosquito vector to assure successful sexual reproduction, which takes places in the mosquito midgut. While these findings provided a first glimpse of a complex mechanism used by Plasmodium to control the host immune attack, it is hitherto not known, how the pathogenic blood stages of the malaria parasite evade destruction by the human complement. We now show that the human complement system represents a severe threat for the replicating blood stages, particularly for the reinvading merozoites, with complement factor C3b accumulating on the surfaces of the intraerythrocytic schizonts as well as of free merozoites. C3b accumulation initiates terminal complement complex formation, in consequence resulting in blood stage lysis. To inactivate C3b, the parasites bind FH as well as related proteins FHL‐1 and CFHR‐1 to their surface, and FH binding is trypsin‐resistant. Schizonts acquire FH via two contact sites, which involve CCP modules 5 and 20. Blockage of FH‐mediated protection via anti‐FH antibodies results in significantly impaired blood stage replication, pointing to the plasmodial complement evasion machinery as a promising malaria vaccine target. 相似文献
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Oliveira Sílvia Ardais Ana Paula Bastos Clarissa Ribeiro Gazal Marta Jansen Karen de Mattos Souza Luciano da Silva Ricardo Azevedo Kaster Manuella Pinto Lara Diogo Rizzato Ghisleni Gabriele 《Purinergic signalling》2019,15(1):37-44
Purinergic Signalling - Genetic variants involved in adenosine metabolism and its receptors were associated with increased risk for psychiatric disorders, including anxiety, depression, and... 相似文献
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Torsten Schubert Stephan H. von Reuß Cindy Kunze Christian Paetz Stefan Kruse Peggy Brand-Schön Anita Mac Nelly Jörg Nüske Gabriele Diekert 《Microbial biotechnology》2019,12(2):346-359
Cobamides (Cbas) are essential cofactors of reductive dehalogenases (RDases) in organohalide-respiring bacteria (OHRB). Changes in the Cba structure can influence RDase function. Here, we report on the cofactor versatility or selectivity of Desulfitobacterium RDases produced either in the native organism or heterologously. The susceptibility of Desulfitobacterium hafniense strain DCB-2 to guided Cba biosynthesis (i.e. incorporation of exogenous Cba lower ligand base precursors) was analysed. Exogenous benzimidazoles, azabenzimidazoles and 4,5-dimethylimidazole were incorporated by the organism into Cbas. When the type of Cba changed, no effect on the turnover rate of the 3-chloro-4-hydroxy-phenylacetate-converting enzyme RdhA6 and the 3,5-dichlorophenol-dehalogenating enzyme RdhA3 was observed. The impact of the amendment of Cba lower ligand precursors on RDase function was also investigated in Shimwellia blattae, the Cba producer used for the heterologous production of Desulfitobacterium RDases. The recombinant tetrachloroethene RDase (PceAY51) appeared to be non-selective towards different Cbas. However, the functional production of the 1,2-dichloroethane-dihaloeliminating enzyme (DcaA) of Desulfitobacterium dichloroeliminans was completely prevented in cells producing 5,6-dimethylbenzimidazolyl-Cba, but substantially enhanced in cells that incorporated 5-methoxybenzimidazole into the Cba cofactor. The results of the study indicate the utilization of a range of different Cbas by Desulfitobacterium RDases with selected representatives apparently preferring distinct Cbas. 相似文献
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Hendrike Dürichen Gabriele Diekert Sandra Studenik 《Protein science : a publication of the Protein Society》2019,28(10):1902-1908
Corrinoids are essential cofactors of enzymes involved in the C1 metabolism of anaerobes. The active, super‐reduced [CoI] state of the corrinoid cofactor is highly sensitive to autoxidation. In O‐demethylases, the oxidation to inactive [CoII] is reversed by an ATP‐dependent electron transfer catalyzed by the activating enzyme (AE). The redox potential changes of the corrinoid cofactor, which occur during this reaction, were studied by potentiometric titration coupled to UV/visible spectroscopy. By applying europium(II)–diethylenetriaminepentaacetic acid (DTPA) as a reductant, we were able to determine the midpoint potential of the [CoII]/[CoI] couple of the protein‐bound corrinoid cofactor in the absence and presence of AE and/or ATP. The data revealed that the transfer of electrons from a physiological donor to the corrinoid as the electron‐accepting site is achieved by increasing the potential of the corrinoid cofactor from ?530 ± 15 mV to ?250 ± 10 mV (ESHE, pH 7.5). The first 50 to 100 mV of the shift of the redox potential seem to be caused by the interaction of nucleotide‐bound AE with the corrinoid protein or its cofactor. The remaining 150–200 mV had to be overcome by the chemical energy of ATP hydrolysis. The experiments revealed that Eu(II)–DTPA, which was already known as a powerful reducing agent, is a suitable electron donor for titration experiments of low‐potential redox centers. Furthermore, the results of this study will contribute to the understanding of thermodynamically unfavorable electron transfer processes driven by the power of ATP hydrolysis. 相似文献
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Patil Satish Sawant Sarvesh Hauff Karlheinz Hampp Gabriele 《Probiotics and antimicrobial proteins》2019,11(4):1124-1131
Probiotics and Antimicrobial Proteins - Hylak® forte is a postbiotic that inhibits the growth of pathogenic bacteria by reducing intestinal pH. It is assumed the potential presence of... 相似文献