Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 6-mer - A3B3 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 293.00 kDa 
• Atom Count: 18645 
• Residue Count: 2405 
• Unique protein chains: 2

3PXI

Structure of MecA108:ClpC

• DOI: 10.2210/pdb3PXI/pdb

• Classification: PROTEIN BINDING
• Organism(s): Bacillus subtilis
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2010-12-09 Released: 2011-03-16 
• Deposition Author(s): Wang, F., Mei, Z.Q., Wang, J.W., Shi, Y.G.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 6.93 Å
• R-Value Free: 0.422 
• R-Value Work: 0.407 
• R-Value Observed: 0.408 

Literature

Structure and mechanism of the hexameric MecA-ClpC molecular machine.

Wang, F., Mei, Z.Q., Qi, Y., Yan, C.G., Hu, Q., Wang, J.W., Shi, Y.G.

(2011) Nature 471: 331-335

• PubMed: 21368759 
• DOI: 10.1038/nature09780
• Primary Citation of Related Structures:  
  3PXG, 3PXI, 2Y1R, 2Y1Q


• PubMed Abstract: 
  

Regulated proteolysis by ATP-dependent proteases is universal in all living cells. Bacterial ClpC, a member of the Clp/Hsp100 family of AAA+ proteins (ATPases associated with diverse cellular activities) with two nucleotide-binding domains (D1 and D2), requires the adaptor protein MecA for activation and substrate targeting. The activated, hexameric MecA-ClpC molecular machine harnesses the energy of ATP binding and hydrolysis to unfold specific substrate proteins and translocate the unfolded polypeptide to the ClpP protease for degradation. Here we report three related crystal structures: a heterodimer between MecA and the amino domain of ClpC, a heterododecamer between MecA and D2-deleted ClpC, and a hexameric complex between MecA and full-length ClpC. In conjunction with biochemical analyses, these structures reveal the organizational principles behind the hexameric MecA-ClpC complex, explain the molecular mechanisms for MecA-mediated ClpC activation and provide mechanistic insights into the function of the MecA-ClpC molecular machine. These findings have implications for related Clp/Hsp100 molecular machines.

---

Organizational Affiliation: 

Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Adapter protein mecA 1	a, b, c	111	Bacillus subtilis	Mutation(s): 0  Gene Names: mecA, BSU11520
Find proteins for P37958 (Bacillus subtilis (strain 168)) Explore P37958  Go to UniProtKB:  P37958

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Negative regulator of genetic competence ClpC/MecB	A, B, C	758	Bacillus subtilis	Mutation(s): 2  Gene Names: clpC, mecB, BSU00860
Find proteins for P37571 (Bacillus subtilis (strain 168)) Explore P37571  Go to UniProtKB:  P37571

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 6.93 Å
• R-Value Free: 0.422 
• R-Value Work: 0.407 
• R-Value Observed: 0.408 
• Space Group: P 6₅ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 141.806	α = 90
b = 141.806	β = 90
c = 656.078	γ = 120

Software Package:

Software Name	Purpose
BSS	data collection
PHASER	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2010-12-09 
• Released Date: 2011-03-16 
Deposition Author(s): Wang, F., Mei, Z.Q., Wang, J.W., Shi, Y.G.

Revision History 

• Version 1.0: 2011-03-16
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2012-06-27
  Changes: Database references