1TWB

SspB disulfide crosslinked to an ssrA degradation tag


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Nucleotide-Dependent Substrate Handoff from the SspB Adaptor to the AAA+ ClpXP Protease.

Bolon, D.N.Grant, R.A.Baker, T.A.Sauer, R.T.

(2004) Mol.Cell 16: 343-350

  • DOI: 10.1016/j.molcel.2004.10.001

  • PubMed Abstract: 
  • The SspB adaptor enhances ClpXP degradation by binding the ssrA degradation tag of substrates and the AAA+ ClpX unfoldase. To probe the mechanism of substrate delivery, we engineered a disulfide bond between the ssrA tag and SspB and demonstrated oth ...

    The SspB adaptor enhances ClpXP degradation by binding the ssrA degradation tag of substrates and the AAA+ ClpX unfoldase. To probe the mechanism of substrate delivery, we engineered a disulfide bond between the ssrA tag and SspB and demonstrated otherwise normal interactions by solving the crystal structure. Although the covalent link prevents adaptor.substrate dissociation, ClpXP degraded GFP-ssrA that was disulfide bonded to the adaptor. Thus, crosslinked substrate must be handed directly from SspB to ClpX. The ssrA tag in the covalent adaptor complex interacted with ClpX.ATPgammaS but not ClpX.ADP, suggesting that handoff occurs in the ATP bound enzyme. By contrast, SspB alone bound ClpX in both nucleotide states. Similar handoff mechanisms will undoubtedly be used by many AAA+ adaptors and enzymes, allowing assembly of delivery complexes in either nucleotide state, engagement of the recognition tag in the ATP state, and application of an unfolding force to the attached protein following hydrolysis.


    Organizational Affiliation

    Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Stringent starvation protein B homolog
A, B
110Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)Mutation(s): 1 
Gene Names: sspB
Find proteins for P45206 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd))
Go to UniProtKB:  P45206
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
ssrA peptide
C, D
8N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.235 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 68.237α = 90.00
b = 68.237β = 90.00
c = 110.384γ = 120.00
Software Package:
Software NamePurpose
HKL-2000data reduction
AMoREphasing
SCALEPACKdata scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-11-16
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance