title: Crystallization and preliminary X-ray analysis of the Escherichia coli adaptor protein ClpS, free and in complex with the N-terminal domain of ClpA.
abstract: Protein degradation in Escherichia coli is accomplished by a handful of large oligomeric complexes. In most cases, these proteolytic machines are comprised of a chaperone (e.g. ClpA) that is required to prepare the substrate for degradation by the peptidase (e.g. ClpP). Recently, it was shown that the substrate recognition of the chaperone ClpA could be modified by the adaptor protein ClpS. To investigate the structural implications of this change in substrate specificity, ClpS was crystallized alone and in complex with the N-terminal domain of ClpA (ClpA(N)). Crystals of ClpS diffract to 2.9 A resolution and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 82.63, b = 145.67, c = 152.31 A. Two different crystal forms of the ClpA(N)-ClpS complex were characterized. Crystal form I (CFI) belongs to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 91.63, b = 112.47, c = 38.47 A; data to 1.92 A resolution were collected. Crystals of form II (CFII) belong to space group P4(1/3)2(1)2, with unit-cell parameters a = b = 93.57, c = 78.77 A, and diffract to 1.85 A resolution. Data sets collected from heavy-atom derivatives of CFI indicated the incorporation of Pt and Hg atoms. Structure solution using MIR and MAD methods is currently under way.
authors.affiliation: EMBL Outstation Grenoble, 6 Rue Jules Horowitz, BP 181, 38042 Grenoble CEDEX 9, France. zeth@biochem.mpg.de
authors.forename: Kornelius
authors.initials: K
authors.lastname: Zeth
authors.forename: David A
authors.initials: DA
authors.lastname: Dougan
authors.forename: Stephen
authors.initials: S
authors.lastname: Cusack
authors.forename: Bernd
authors.initials: B
authors.lastname: Bukau
authors.forename: Raimond B
authors.initials: RB
authors.lastname: Ravelli
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods*; D049071:Endopeptidase Clp; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012697:Serine Endopeptidases / Q000737:chemistry*
chemical_list: D002352:Carrier Proteins; C454820:ClpS protein, E coli; D029968:Escherichia coli Proteins; D012697:Serine Endopeptidases; C483568:ClpA protease, E coli; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases