3mh4
HtrA proteases are activated by a conserved mechanism that can be triggered by distinct molecular cuesHtrA proteases are activated by a conserved mechanism that can be triggered by distinct molecular cues
Structural highlights
FunctionDEGP_ECOLI DegP acts as a chaperone at low temperatures but switches to a peptidase (heat shock protein) at higher temperatures. It degrades transiently denatured and unfolded proteins which accumulate in the periplasm following heat shock or other stress conditions. DegP is efficient with Val-Xaa and Ile-Xaa peptide bonds, suggesting a preference for beta-branched side chain amino acids. Only unfolded proteins devoid of disulfide bonds appear capable of being cleaved, thereby preventing non-specific proteolysis of folded proteins. Its proteolytic activity is essential for the survival of cells at elevated temperatures. It can degrade IciA, ada, casein, globin and PapA. DegP shares specificity with DegQ. DegP is also involved in the biogenesis of partially folded outer-membrane proteins (OMP).[1] [2] [3] [4] [5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedHtrA proteases are tightly regulated proteolytic assemblies that are essential for maintaining protein homeostasis in extracytosolic compartments. Though HtrA proteases have been characterized in detail, their precise molecular mechanism for switching between different functional states is still unknown. To address this, we carried out biochemical and structural studies of DegP from Escherichia coli. We show that effector-peptide binding to the PDZ domain of DegP induces oligomer conversion from resting hexameric DegP6 into proteolytically active 12-mers and 24-mers (DegP12/24). Moreover, our data demonstrate that a specific protease loop (L3) functions as a conserved molecular switch of HtrA proteases. L3 senses the activation signal-that is, the repositioned PDZ domain of substrate-engaged DegP12/24 or the binding of allosteric effectors to regulatory HtrA proteases such as DegS-and transmits this information to the active site. Implications for protein quality control and regulation of oligomeric enzymes are discussed. HtrA proteases have a conserved activation mechanism that can be triggered by distinct molecular cues.,Krojer T, Sawa J, Huber R, Clausen T Nat Struct Mol Biol. 2010 Jul;17(7):844-52. Epub 2010 Jun 27. PMID:20581825[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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