3o2h
From Proteopedia
E. coli ClpS in complex with a Leu N-end rule peptide
Structural highlights
Function[CLPS_ECOLI] Involved in the modulation of the specificity of the ClpAP-mediated ATP-dependent protein degradation. [DPS_ECOLI] During stationary phase, binds the chromosome non-specifically, forming a highly ordered and stable dps-DNA co-crystal within which chromosomal DNA is condensed and protected from diverse damages. It protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral, which can be released after reduction. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction. Dps also protects the cell from UV and gamma irradiation, iron and copper toxicity, thermal stress and acid and base shocks. Also shows a weak catalase activity.[1] [2] [3] [4] Publication Abstract from PubMedIn Escherichia coli, the ClpAP protease, together with the adaptor protein ClpS, is responsible for the degradation of proteins bearing an amino-terminal destabilizing amino acid (N-degron). Here, we determined the three-dimensional structures of ClpS in complex with three peptides, each having a different destabilizing residue--Leu, Phe or Trp--at its N terminus. All peptides, regardless of the identity of their N-terminal residue, are bound in a surface pocket on ClpS in a stereo-specific manner. Several highly conserved residues in this binding pocket interact directly with the backbone of the N-degron peptide and hence are crucial for the binding of all N-degrons. By contrast, two hydrophobic residues define the volume of the binding pocket and influence the specificity of ClpS. Taken together, our data suggest that ClpS has been optimized for the binding and delivery of N-degrons containing an N-terminal Phe or Leu. Structural basis of N-end rule substrate recognition in Escherichia coli by the ClpAP adaptor protein ClpS.,Schuenemann VJ, Kralik SM, Albrecht R, Spall SK, Truscott KN, Dougan DA, Zeth K EMBO Rep. 2009 May;10(5):508-14. Epub 2009 Apr 17. PMID:19373253[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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