3cs0
Crystal structure of DegP24Crystal structure of DegP24
Structural highlights
Function[DEGP_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 PubMedAll organisms have to monitor the folding state of cellular proteins precisely. The heat-shock protein DegP is a protein quality control factor in the bacterial envelope that is involved in eliminating misfolded proteins and in the biogenesis of outer-membrane proteins. Here we describe the molecular mechanisms underlying the regulated protease and chaperone function of DegP from Escherichia coli. We show that binding of misfolded proteins transforms hexameric DegP into large, catalytically active 12-meric and 24-meric multimers. A structural analysis of these particles revealed that DegP represents a protein packaging device whose central compartment is adaptable to the size and concentration of substrate. Moreover, the inner cavity serves antagonistic functions. Whereas the encapsulation of folded protomers of outer-membrane proteins is protective and might allow safe transit through the periplasm, misfolded proteins are eliminated in the molecular reaction chamber. Oligomer reassembly and concomitant activation on substrate binding may also be critical in regulating other HtrA proteases implicated in protein-folding diseases. Structural basis for the regulated protease and chaperone function of DegP.,Krojer T, Sawa J, Schafer E, Saibil HR, Ehrmann M, Clausen T Nature. 2008 Jun 12;453(7197):885-90. Epub 2008 May 21. PMID:18496527[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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