The intrinsically disordered Tarp protein from chlamydia binds actin with a partially preformed helix.
Sci Rep
; 8(1): 1960, 2018 01 31.
Article
in En
| MEDLINE
| ID: mdl-29386631
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 11 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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Chlamydia trachomatis
/
Actins
/
Intrinsically Disordered Proteins
Type of study:
Prognostic_studies
Language:
En
Journal:
Sci Rep
Year:
2018
Document type:
Article
Affiliation country:
United kingdom