1sot
From Proteopedia
Crystal Structure of the DegS stress sensor
Structural highlights
FunctionDEGS_ECOLI When heat shock or other environmental stresses disrupt protein folding in the periplasm, DegS senses the accumulation of unassembled outer membrane porins (OMPs) and then initiates RseA (anti sigma-E factor) degradation by cleaving it in its periplasmic domain, making it an attractive substrate for subsequent cleavage by RseP. This cascade that ultimately leads to the sigma-E-driven expression of a variety of factors dealing with folding stress in the periplasm and OMP assembly.[1] [2] 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 PubMedGram-negative bacteria respond to misfolded proteins in the cell envelope with the sigmaE-driven expression of periplasmic proteases/chaperones. Activation of sigmaE is controlled by a proteolytic cascade that is initiated by the DegS protease. DegS senses misfolded protein in the periplasm, undergoes autoactivation, and cleaves the antisigma factor RseA. Here, we present the crystal structures of three distinct states of DegS from E. coli. DegS alone exists in a catalytically inactive form. Binding of stress-signaling peptides to its PDZ domain induces a series of conformational changes that activates protease function. Backsoaking of crystals containing the DegS-activator complex revealed the presence of an active/inactive hybrid structure and demonstrated the reversibility of activation. Taken together, the structural data illustrate in molecular detail how DegS acts as a periplasmic stress sensor. Our results suggest a novel regulatory role for PDZ domains and unveil a novel mechanism of reversible protease activation. Crystal structure of the DegS stress sensor: How a PDZ domain recognizes misfolded protein and activates a protease.,Wilken C, Kitzing K, Kurzbauer R, Ehrmann M, Clausen T Cell. 2004 May 14;117(4):483-94. PMID:15137941[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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