PDBsum entry 1ksf

Hydrolase, ligand binding protein

PDB id: 1ksf

Contents

Protein chain

714 a.a. *

Ligands

MET

PGE ×2

ADP ×2

IPA ×5

Metals

_MG ×2

Waters ×242

* Residue conservation analysis

PDB id:

1ksf

Name:

Hydrolase, ligand binding protein

Title:

Crystal structure of clpa, an hsp100 chaperone and regulator of clpap protease: structural basis of differences in function of the two aaa+ atpase domains

Structure:

Atp-dependent clp protease atp-binding subunit clpa. Chain: x. Synonym: endopeptidase clp atp-binding. Atp-binding component of serine protease. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.60Å R-factor: 0.221 R-free: 0.304

Authors:

F.Guo,M.R.Maurizi,L.Esser,D.Xia

Key ref:

F.Guo et al. (2002). Crystal structure of ClpA, an Hsp100 chaperone and regulator of ClpAP protease. J Biol Chem, 277, 46743-46752. PubMed id: 12205096 DOI: 10.1074/jbc.M207796200

Date:

12-Jan-02 Release date: 27-Sep-02

Protein chain

P0ABH9  (CLPA_ECOLI) -  ATP-dependent Clp protease ATP-binding subunit ClpA from Escherichia coli (strain K12)

Seq: 758 a.a.

Struc: 714 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1074/jbc.M207796200

J Biol Chem 277:46743-46752 (2002)

PubMed id: 12205096

Crystal structure of ClpA, an Hsp100 chaperone and regulator of ClpAP protease.

F.Guo, M.R.Maurizi, L.Esser, D.Xia.

ABSTRACT

Escherichia coli ClpA, an Hsp100/Clp chaperone and an integral component of the ATP-dependent ClpAP protease, participates in regulatory protein degradation and the dissolution and degradation of protein aggregates. The crystal structure of the ClpA subunit reveals an N-terminal domain with pseudo-twofold symmetry and two AAA(+) modules (D1 and D2) each consisting of a large and a small sub-domain with ADP bound in the sub-domain junction. The N-terminal domain interacts with the D1 domain in a manner similar to adaptor-binding domains of other AAA(+) proteins. D1 and D2 are connected head-to-tail consistent with a cooperative and vectorial translocation of protein substrates. In a planar hexamer model of ClpA, built by assembling ClpA D1 and D2 into homohexameric rings of known structures of AAA(+) modules, the differences in D1-D1 and D2-D2 interfaces correlate with their respective contributions to hexamer stability and ATPase activity.

Selected figure(s)

Figure 5.
Fig. 5. Hexameric model of ClpA. Electrostatic potential surface of the modeled planar ClpA hexagon as rendered in GRASP, with negative potential in red, positive in blue, and neutral in white. a, the hexagonal ring is viewed along the 6-fold axis with the D1 domains facing out. The hexagon has a crenated edge and maximum diameter of 170 Å. The larger crenations are made by the six N-domains, which are attached to the outer edge of the D1 domains; the smaller crenations are formed by extensions of the D2-small domains. b, the D2 side is facing out, showing the wide opening of the central cavity (red) and residues forming part of the ClpP loop (yellow). c, side view of the modeled ClpA hexagonal ring. The height is about 87 Å. The six subunits are shown in different colors. D1 and D2 from the same ClpA subunit are tilted with respect to the ring axis and make little contact with each other. Each domain makes extensive contacts with both D1 and D2 of a neighboring subunit. d, cross section through the center and parallel to the 6-fold axis of the modeled ClpA hexagonal ring. The surface of the central cavity is colored to show the three negatively charged belts (red) and the hydrophobic surfaces surrounding the channels (gray). The borders of the cavity are outlined in black. The two constrictions and the two compartments are as labeled. The positions for the three remaining ClpP loop are indicated in yellow.

Figure 6.
Fig. 6. A hypothetical model describing transitions of ClpA subunits in solution to form a spiral in crystal in the presence of ADP and to assemble into a planar hexamer in solution in the presence of ATP. ClpA subunits are postulated to undergo an open and a closed conformation by rotating D2 with respect to D1 via the hinge between two domains.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 46743-46752) copyright 2002.

Figures were selected by an automated process.