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dc.contributor.authorDas, D.
dc.contributor.authorKrantz, B.A.
dc.date.accessioned2019-07-15T16:12:14Z
dc.date.available2019-07-15T16:12:14Z
dc.date.issued2017
dc.identifier.urihttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85010867860&doi=10.1016%2fj.jmb.2017.01.015&partnerID=40&md5=bcebae77748b6b10c23655a47f2e914a
dc.identifier.urihttp://hdl.handle.net/10713/9963
dc.description.abstractIn order for many proteins to move across hydrophobic membrane bilayers, they must be unfolded and translocated by a membrane-embedded channel. These translocase channels interact with the substrate proteins they translocate via hydrophobic pore loops and cleft structures called clamps. The molecular basis for how clamps facilitate unfolding and translocation is poorly understood. Anthrax toxin is composed of three proteins, a translocase channel-forming subunit, called protective antigen (PA), and two substrate proteins, called lethal factor (LF) and edema factor. Oligomeric PA forms a large channel that contains three types of polypeptide clamp sites: an α clamp, a phenylalanine clamp, and a charge clamp. Currently, it is thought that these clamp sites operate allosterically and promote translocation via an allosteric helix compression mechanism. Here, we report on the substrate secondary structure dependence of the PA channel. Peptides derived from regions of LF with high α-helical content bound cooperatively, but those derived from β-sheet regions in LF did not, suggesting that an allosteric site preferentially recognizes α-helical structure over β-sheet structure. Peptides derived from helical sites in LF showed increasingly longer single-channel blockades as a function of peptide concentration, a result that was consistent with stronger clamping behavior and reduced backsliding. Moreover, peptides derived from helical regions of LF translocated more efficiently than peptides derived from β-sheet regions of LF. Overall, in support of the allosteric helix compression model, we find that the channel prefers α-helical sequences over β-sheet sequences. Copyright 2017 The Authorsen_US
dc.description.sponsorshipThis work was supported by an NIH grant, R01 AI077703.en_US
dc.description.urihttps://www.doi.org/10.1016/j.jmb.2017.01.015en_US
dc.language.isoen_USen_US
dc.publisherAcademic Pressen_US
dc.relation.ispartofJournal of Molecular Biology
dc.subjectallosteryen_US
dc.subjectanthrax toxinen_US
dc.subjectBacillus anthracisen_US
dc.subjectelectrophysiologyen_US
dc.subjectprotective antigenen_US
dc.titleSecondary Structure Preferences of the Anthrax Toxin Protective Antigen Translocaseen_US
dc.typeArticleen_US
dc.identifier.doi10.1016/j.jmb.2017.01.015
dc.identifier.pmid28115202


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