Exploring Host-Guest Interactions within a 600 kDa DegP Protease Cage Complex Using Hydrodynamics Measurements and...

Area of Science:

• Bacterial protein homeostasis
• Molecular chaperones
• Protease function

Background:

• DegP protease-chaperone maintains protein homeostasis in Gram-negative bacteria.
• DegP forms cage-like complexes to capture and process client proteins.
• Limited understanding of client protein dynamics within DegP cages.

Purpose of the Study:

• Investigate host-guest interactions within DegP cages.
• Elucidate the relationship between client dynamics and DegP function.
• Characterize DegP activation upon client engagement.

Main Methods:

• Hydrodynamics measurements
• Solution nuclear magnetic resonance (NMR) spectroscopy
• Proteolytic activity assays

Main Results:

• DegP cages assemble cooperatively with minimal intermediates upon client binding.
• The N-terminal region of client proteins is flexible and unfolded within the cage.
• Client engagement triggers a structural transition and activation of DegP protease domains.

Conclusions:

• DegP functions as a dynamic molecular machine.
• DegP stabilizes unfolded client states through C-terminal interactions.
• DegP activation leads to efficient client protein cleavage.