PDBsum entry 4i4l

Motor protein

PDB id: 4i4l

Contents

Protein chains

299 a.a.

305 a.a.

Ligands

ADP

SO4 ×6

PDB id:

4i4l

Name:

Motor protein

Title:

Crystal structure of nucleotide-bound w-w-w clpx hexamer

Structure:

Atp-dependent clp protease atp-binding subunit clpx. Chain: a, b, c, d, e, f. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Gene: b0438, clpx, jw0428, lopc. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

3.70Å R-factor: 0.301 R-free: 0.323

Authors:

S.E.Glynn,A.R.Nager,B.S.Stinson,K.R.Schmitz,T.A.Baker,R.T.Sauer

Key ref:

B.M.Stinson et al. (2013). Nucleotide binding and conformational switching in the hexameric ring of a AAA+ machine. Cell, 153, 628-639. PubMed id: 23622246 DOI: 10.1016/j.cell.2013.03.029

Date:

27-Nov-12 Release date: 15-May-13

Protein chain

P0A6H1  (CLPX_ECOLI) -  ATP-dependent Clp protease ATP-binding subunit ClpX from Escherichia coli (strain K12)

Seq: 424 a.a.

Struc: 299 a.a.*

Protein chains

P0A6H1  (CLPX_ECOLI) -  ATP-dependent Clp protease ATP-binding subunit ClpX from Escherichia coli (strain K12)

Seq: 424 a.a.

Struc: 305 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

DOI no: 10.1016/j.cell.2013.03.029

Cell 153:628-639 (2013)

PubMed id: 23622246

Nucleotide binding and conformational switching in the hexameric ring of a AAA+ machine.

B.M.Stinson, A.R.Nager, S.E.Glynn, K.R.Schmitz, T.A.Baker, R.T.Sauer.

ABSTRACT

ClpX, a AAA+ ring homohexamer, uses the energy of ATP binding and hydrolysis to power conformational changes that unfold and translocate target proteins into the ClpP peptidase for degradation. In multiple crystal structures, some ClpX subunits adopt nucleotide-loadable conformations, others adopt unloadable conformations, and each conformational class exhibits substantial variability. Using mutagenesis of individual subunits in covalently tethered hexamers together with fluorescence methods to assay the conformations and nucleotide-binding properties of these subunits, we demonstrate that dynamic interconversion between loadable and unloadable conformations is required to couple ATP hydrolysis by ClpX to mechanical work. ATP binding to different classes of subunits initially drives staged allosteric changes, which set the conformation of the ring to allow hydrolysis and linked mechanical steps. Subunit switching between loadable and unloadable conformations subsequently isomerizes or resets the configuration of the nucleotide-loaded ring and is required for mechanical function.