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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]}

References

1. ↑ Lipinska B, Zylicz M, Georgopoulos C. The HtrA (DegP) protein, essential for Escherichia coli survival at high temperatures, is an endopeptidase. J Bacteriol. 1990 Apr;172(4):1791-7. PMID:2180903
2. ↑ Kolmar H, Waller PR, Sauer RT. The DegP and DegQ periplasmic endoproteases of Escherichia coli: specificity for cleavage sites and substrate conformation. J Bacteriol. 1996 Oct;178(20):5925-9. PMID:8830688
3. ↑ Spiess C, Beil A, Ehrmann M. A temperature-dependent switch from chaperone to protease in a widely conserved heat shock protein. Cell. 1999 Apr 30;97(3):339-47. PMID:10319814
4. ↑ Krojer T, Pangerl K, Kurt J, Sawa J, Stingl C, Mechtler K, Huber R, Ehrmann M, Clausen T. Interplay of PDZ and protease domain of DegP ensures efficient elimination of misfolded proteins. Proc Natl Acad Sci U S A. 2008 Jun 3;105(22):7702-7. doi:, 10.1073/pnas.0803392105. Epub 2008 May 27. PMID:18505836 doi:10.1073/pnas.0803392105
5. ↑ Pan KL, Hsiao HC, Weng CL, Wu MS, Chou CP. Roles of DegP in prevention of protein misfolding in the periplasm upon overexpression of penicillin acylase in Escherichia coli. J Bacteriol. 2003 May;185(10):3020-30. PMID:12730160
6. ↑ Krojer T, Sawa J, Schafer E, Saibil HR, Ehrmann M, Clausen T. Structural basis for the regulated protease and chaperone function of DegP. Nature. 2008 Jun 12;453(7197):885-90. Epub 2008 May 21. PMID:18496527 doi:10.1038/nature07004