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    The intrinsically disordered Tarp protein from chlamydia binds actin with a partially preformed helix

    Tolchard, J. and Walpole, S.J. and Miles, Andrew J. and Maytum, R. and Eaglen, L.A. and Hackstadt, T. and Wallace, Bonnie A. and Blumenschein, T.M.A. (2018) The intrinsically disordered Tarp protein from chlamydia binds actin with a partially preformed helix. Scientific Reports 8 (1), p. 1960. ISSN 2045-2322.

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    Abstract

    Tarp (translocated actin recruiting phosphoprotein) is an effector protein common to all chlamydial species that functions to remodel the host-actin cytoskeleton during the initial stage of infection. In C. trachomatis, direct binding to actin monomers has been broadly mapped to a 100-residue region (726-825) which is predicted to be predominantly disordered, with the exception of a ~10-residue α-helical patch homologous to other WH2 actin-binding motifs. Biophysical investigations demonstrate that a Tarp726-825 construct behaves as a typical intrinsically disordered protein; within it, NMR relaxation measurements and chemical shift analysis identify the ten residue WH2-homologous region to exhibit partial α-helix formation. Isothermal titration calorimetry experiments on the same construct in the presence of monomeric G-actin show a well defined binding event with a 1:1 stoichiometry and Kd of 102 nM, whilst synchrotron radiation circular dichroism spectroscopy suggests the binding is concomitant with an increase in helical secondary structure. Furthermore, NMR experiments in the presence of G-actin indicate this interaction affects the proposed WH2-like α-helical region, supporting results from in silico docking calculations which suggest that, when folded, this α-helix binds within the actin hydrophobic cleft as seen for other actin-associated proteins.

    Metadata

    Item Type: Article
    School: Birkbeck Schools and Departments > School of Science > Biological Sciences
    SWORD Depositor: Mr Joe Tenant
    Depositing User: Administrator
    Date Deposited: 13 Feb 2018 14:55
    Last Modified: 27 Jul 2019 06:20
    URI: http://eprints.bbk.ac.uk/id/eprint/21181

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