Structural and theoretical studies indicate that the cylindrical protease ClpP samples extended and compact...

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biology

Background:

• The ClpP protease is a highly conserved molecular machine essential for cellular protein homeostasis.
• Its tetradecameric structure, formed by two heptameric rings, is crucial for its proteolytic activity.
• Previous models proposed dynamic conformational changes for substrate processing and product release.

Purpose of the Study:

• To investigate the structural basis of ClpP protease dynamics.
• To elucidate the mechanism of peptide product egress from the protease core.
• To understand the conformational switch between active and inactive states of ClpP.

Main Methods:

• X-ray crystallography of a disulfide-bonded Escherichia coli ClpP mutant.
• Comparative structural analysis with ClpP structures from various species.
• Normal mode analysis to predict protein dynamics.

Main Results:

• A disulfide-bonded E. coli ClpP mutant adopted a compact, inactive conformation.
• This structure resembles ClpP from Streptococcus pneumoniae, Mycobacterium tuberculosis, and Plasmodium falciparum.
• Structural and computational data support a dynamic model of ClpP switching between extended (active) and compact (inactive) states.

Conclusions:

• The ClpP protease exists in dynamic equilibrium between active and inactive conformations.
• The compact state facilitates the release of peptide products.
• Understanding these dynamics is key to ClpP's function in protein degradation.