3J3R

Structural dynamics of the MecA-ClpC complex revealed by cryo-EM


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 9.4 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural dynamics of the MecA-ClpC complex: a type II AAA+ protein unfolding machine

Liu, J.Mei, Z.Li, N.Qi, Y.Xu, Y.Shi, Y.Wang, F.Lei, J.Gao, N.

(2013) J.Biol.Chem. 288: 17597-17608

  • DOI: 10.1074/jbc.M113.458752
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The MecA-ClpC complex is a bacterial type II AAA(+) molecular machine responsible for regulated unfolding of substrates, such as transcription factors ComK and ComS, and targeting them to ClpP for degradation. The six subunits of the MecA-ClpC comple ...

    The MecA-ClpC complex is a bacterial type II AAA(+) molecular machine responsible for regulated unfolding of substrates, such as transcription factors ComK and ComS, and targeting them to ClpP for degradation. The six subunits of the MecA-ClpC complex form a closed barrel-like structure, featured with three stacked rings and a hollow passage, where substrates are threaded and translocated through successive pores. Although the general concepts of how polypeptides are unfolded and translocated by internal pore loops of AAA(+) proteins have long been conceived, the detailed mechanistic model remains elusive. With cryoelectron microscopy, we captured four different structures of the MecA-ClpC complexes. These complexes differ in the nucleotide binding states of the two AAA(+) rings and therefore might presumably reflect distinctive, representative snapshots from a dynamic unfolding cycle of this hexameric complex. Structural analysis reveals that nucleotide binding and hydrolysis modulate the hexameric complex in a number of ways, including the opening of the N-terminal ring, the axial and radial positions of pore loops, the compactness of the C-terminal ring, as well as the relative rotation between the two nucleotide-binding domain rings. More importantly, our structural and biochemical data indicate there is an active allosteric communication between the two AAA(+) rings and suggest that concerted actions of the two AAA(+) rings are required for the efficiency of the substrate unfolding and translocation. These findings provide important mechanistic insights into the dynamic cycle of the MecA-ClpC unfoldase and especially lay a foundation toward the complete understanding of the structural dynamics of the general type II AAA(+) hexamers.


    Organizational Affiliation

    Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Adapter protein MecA 1
1, 2, 3, 4, 5, 6
218Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: mecA
Find proteins for P37958 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P37958
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Negative regulator of genetic competence ClpC/MecB
A, B, C, D, E, F
810Bacillus subtilis (strain 168)Mutation(s): 2 
Gene Names: clpC (mecB)
Find proteins for P37571 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P37571
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 9.4 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-05-15
    Type: Initial release
  • Version 1.1: 2013-08-28
    Type: Database references
  • Version 1.2: 2014-10-22
    Type: Other