Structural insights into the Clp protein degradation machinery

Area of Science:

• Bacterial protein degradation pathways
• Molecular mechanisms of proteostasis
• Structural biology of protease systems

Background:

• The Clp protease system maintains bacterial proteostasis, essential for homeostasis and pathogenesis.
• ClpP proteases and Clp-ATPases (like ClpC1) form complexes to degrade proteins.
• Streptomyces hawaiiensis possesses a complex ClpP system and produces ADEP1, an antibiotic affecting ClpP activity.

Purpose of the Study:

• To elucidate the structural and mechanistic details of the assembled Clp protease machinery from Streptomyces hawaiiensis.
• To investigate the interaction between the ClpP1P2 chamber, ClpC1 ATPase, and the ADEP1 molecule.
• To understand the mechanism of substrate translocation and ATP hydrolysis within the Clp system.

Main Methods:

• Cryo-electron microscopy (cryo-EM) to determine high-resolution structures.
• Structural analysis of substrate-bound ClpC1:shClpP1P2 complex.
• Structural analysis of shClpP1P2 in complex with ADEP1.

Main Results:

• Detailed structures of shClpP1-shClpP2, shClpP2-ClpC1, and ADEP1-shClpP1/P2 interactions were obtained.
• Conformational changes in ClpC1 during substrate translocation were observed.
• A rotational ATP hydrolysis mechanism, likely driven by D1 ATPase activity, was captured.

Conclusions:

• The study provides unprecedented structural insights into the S. hawaiiensis Clp protease system and ADEP1 interactions.
• Understanding these mechanisms enhances knowledge of bacterial proteolysis and aids in developing novel antimicrobial drugs.
• Findings contribute to combating bacterial multidrug resistance by targeting essential Clp protease pathways.