Structural basis of DegP-protease temperature-dependent activation

Abstract

Protein quality control is an essential cellular function and it is mainly executed by a large array of proteases and molecular chaperones. One of the bacterial HtrA protein family members, the homo-oligomeric DegP-protease, plays a crucial role in the Escherichia coli (E. coli) protein quality control machinery by removing unfolded proteins or preventing them from aggregation and chaperoning them until they are properly folded within the periplasm. DegP contains two regulatory PDZ domains, which play key roles in substrate recognition as well as in the transformation of DegP to proteolytic cage-like structures. Here, we analyse the interaction and dynamics of the PDZ-domains of DegP underlying this transformation in solution by high-resolution NMR spectroscopy. We identify an interdomain molecular lock guiding the interactions between both PDZ domains, regulated by fine-tuned protein dynamics and potentially conserved in proteins harboring tandem PDZ domains.