[Deborah Byrne]

Hello all,

There is an exciting PhD opportunity in my lab.

Investigation into the structural dynamics-activity relationship of a novel E.coli chaperone of the Secretory pathway

Keywords
Bacterial chaperones, Secretory pathway, Structural dynamics, Protein-Protein interactions, Spin Labeling &
EPR spectroscopy

Summary
YecA is a bacterial molecular chaperone (MC) newly identified in E.coli in 2020. This MC interacts with different proteins synthetized by the ribosome to maintain their unfolded state prior to their periplasmatic
translocation across the membrane (Secretory pathway, Sec). Due to its recent discovery, the mechanism of client protein binding/release from a kinetic point of view including the implication of the structure has not
yet been characterized for YecA. This thesis subject aims to analyze the structural dynamic-activity relationship of YecA by integrative
biophysical approaches. Isothermal Titration Calorimetry (ITC) and Dynamic Light Scattering (DLS) techniques
will be used initially to investigate kinetic and thermodynamic aspects of the substrate recognition
mechanism of YecA. These measurements will determine the affinity strength of YecA for its partners and
discriminate between its possible holdase or unfoldase activity in the Sec pathway. The implication of the
structural dynamics of YecA in its function will be further studied using Site Directed Spin Labeling (SDSL)
associated to EPR spectroscopy. In vitro as well as in bacterial (in-cell) EPR experiments will be conducted to
investigate YecA conformational transitions at the molecular level upon interacting with its partner proteins.
Another aspect of the PhD project involves the development of innovative strategies based on a protein
trans-splicing method to enlarge the domain of application of SDSL-EPR approaches. The integration of all
the results will permit to decipher the chaperone activity of YecA in the Sec pathway and the link between
structural dynamics and its mechanism of action. The complementary nature of the two laboratories is key
to undertake this project and the PhD candidate will have the opportunity to acquire both biochemical and
biophysical knowledge on proteins in an ideal scientific environment.

All applicants to byrne@imm.cnrs.fr & abonucci@imm.cnrs.fr

[Author]

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