Biological Assembly 1  

 3D View: Structure

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 11.49 kDa 
• Atom Count: 655 
• Residue Count: 86 
• Unique protein chains: 1

2KSS

NMR structure of Myxococcus xanthus antirepressor CarS1

• DOI: 10.2210/pdb2KSS/pdb

• Classification: TRANSCRIPTION REGULATOR
• Organism(s): Myxococcus xanthus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2010-01-13 Released: 2010-05-12 
• Deposition Author(s): Jimenez, M., Gonzalez, C., Padmanabhan, S., Leon, E., Navarro-Aviles, G., Elias-Arnanz, M.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 100 
• Conformers Submitted: 20 
• Selection Criteria: target function 

Literature

A bacterial antirepressor with SH3 domain topology mimics operator DNA in sequestering the repressor DNA recognition helix.

Leon, E., Navarro-Aviles, G., Santiveri, C.M., Flores-Flores, C., Rico, M., Gonzalez, C., Murillo, F.J., Elias-Arnanz, M., Jimenez, M.A., Padmanabhan, S.

(2010) Nucleic Acids Res 38: 5226-5241

• PubMed: 20410074 
• DOI: 10.1093/nar/gkq277
• Primary Citation of Related Structures:  
  2KSS


• PubMed Abstract: 
  

Direct targeting of critical DNA-binding elements of a repressor by its cognate antirepressor is an effective means to sequester the repressor and remove a transcription initiation block. Structural descriptions for this, though often proposed for bacterial and phage repressor-antirepressor systems, are unavailable. Here, we describe the structural and functional basis of how the Myxococcus xanthus CarS antirepressor recognizes and neutralizes its cognate repressors to turn on a photo-inducible promoter. CarA and CarH repress the carB operon in the dark. CarS, produced in the light, physically interacts with the MerR-type winged-helix DNA-binding domain of these repressors leading to activation of carB. The NMR structure of CarS1, a functional CarS variant, reveals a five-stranded, antiparallel beta-sheet fold resembling SH3 domains, protein-protein interaction modules prevalent in eukaryotes but rare in prokaryotes. NMR studies and analysis of site-directed mutants in vivo and in vitro unveil a solvent-exposed hydrophobic pocket lined by acidic residues in CarS, where the CarA DNA recognition helix docks with high affinity in an atypical ligand-recognition mode for SH3 domains. Our findings uncover an unprecedented use of the SH3 domain-like fold for protein-protein recognition whereby an antirepressor mimics operator DNA in sequestering the repressor DNA recognition helix to activate transcription.

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Related Citations: 

• 1H, 13C, 15N backbone and side chain resonance assignments of a Myxococcus xanthus antirepressor with no known sequence homologues
  Leon, E., Navarro-Aviles, G., Flores, C., Elias-Arnanz, M., Gonzalez, C., Jimenez, M., Padmanabhan, S.
  (2009) Biomol NMR Assign 3: 37

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Organizational Affiliation: 

Instituto de Química-Física Rocasolano, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Carotenogenesis protein carS	A	106	Myxococcus xanthus	Mutation(s): 0  Gene Names: carS
Find proteins for Q06911 (Myxococcus xanthus) Explore Q06911  Go to UniProtKB:  Q06911

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 100 
• Conformers Submitted: 20 
• Selection Criteria: target function 
• OLDERADO: 2KSS Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2010-01-13 
• Released Date: 2010-05-12 
Deposition Author(s): Jimenez, M., Gonzalez, C., Padmanabhan, S., Leon, E., Navarro-Aviles, G., Elias-Arnanz, M.

Revision History 

• Version 1.0: 2010-05-12
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance