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Molecular basis for the binding and modulation of V-ATPase by a bacterial effector protein
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نویسنده
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zhao j. ,beyrakhova k. ,liu y. ,alvarez c.p. ,bueler s.a. ,xu l. ,xu c. ,boniecki m.t. ,kanelis v. ,luo z.-q. ,cygler m. ,rubinstein j.l.
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منبع
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plos pathogens - 2017 - دوره : 13 - شماره : 6
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چکیده
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Intracellular pathogenic bacteria evade the immune response by replicating within host cells. legionella pneumophila,the causative agent of legionnaires’ disease,makes use of numerous effector proteins to construct a niche supportive of its replication within phagocytic cells. the l. pneumophila effector sidk was identified in a screen for proteins that reduce the activity of the proton pumping vacuolar-type atpases (v-atpases) when expressed in the yeast saccharomyces cerevisae. sidk is secreted by l. pneumophila in the early stages of infection and by binding to and inhibiting the v-atpase,sidk reduces phagosomal acidification and promotes survival of the bacterium inside macrophages. we determined crystal structures of the n-terminal region of sidk at 2.3 å resolution and used single particle electron cryomicroscopy (cryo-em) to determine structures of v-atpase:sidk complexes at ~6.8 å resolution. sidk is a flexible and elongated protein composed of an α-helical region that interacts with subunit a of the v-atpase and a second region of unknown function that is flexibly-tethered to the first. sidk binds v-atpase strongly by interacting via two α-helical bundles at its n terminus with subunit a. in vitro activity assays show that sidk does not inhibit the v-atpase completely,but reduces its activity by ~40%,consistent with the partial v-atpase deficiency phenotype its expression causes in yeast. the cryo-em analysis shows that sidk reduces the flexibility of the a-subunit that is in the ‘open’ conformation. fluorescence experiments indicate that sidk binding decreases the affinity of v-atpase for a fluorescent analogue of atp. together,these results reveal the structural basis for the fine-tuning of v-atpase activity by sidk. © 2017 zhao et al.
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آدرس
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the hospital for sick children research institute,toronto,on,canada,department of medical biophysics,university of toronto,toronto,on,canada,department of biochemistry and biophysics,university of california san francisco,san francisco,ca, United States, department of biochemistry,university of saskatchewan,saskatoon,sk, Canada, department of biological sciences,purdue university,west lafayette,in, United States, department of chemistry,university of toronto,toronto,on,canada,department of chemical and physical sciences,university of toronto mississauga,mississauga,on, Canada, the hospital for sick children research institute,toronto,on, Canada, department of biological sciences,purdue university,west lafayette,in,united states,department of molecular biology and genetics,weill institute for cell and molecular biology,cornell university,ithaca,ny, United States, department of biochemistry,university of saskatchewan,saskatoon,sk, Canada, department of biochemistry,university of saskatchewan,saskatoon,sk, Canada, department of chemistry,university of toronto,toronto,on,canada,department of chemical and physical sciences,university of toronto mississauga,mississauga,on,canada,department of cell and systems biology,university of toronto,toronto,on, Canada, department of biological sciences,purdue university,west lafayette,in, United States, department of biochemistry,university of saskatchewan,saskatoon,sk, Canada, the hospital for sick children research institute,toronto,on,canada,department of medical biophysics,university of toronto,toronto,on,canada,department of biochemistry,university of toronto,toronto,on, Canada
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Authors
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