3K0J

Crystal structure of the E. coli ThiM riboswitch in complex with thiamine pyrophosphate and the U1A crystallization module


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

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This is version 1.1 of the entry. See complete history


Literature

Thermodynamic analysis of ligand binding and ligand binding-induced tertiary structure formation by the thiamine pyrophosphate riboswitch.

Kulshina, N.Edwards, T.E.Ferre-D'Amare, A.R.

(2010) RNA 16: 186-196

  • DOI: 10.1261/rna.1847310
  • Primary Citation of Related Structures:  
    3K0J

  • PubMed Abstract: 
  • The thi-box riboswitch regulates gene expression in response to the intracellular concentration of thiamine pyrophosphate (TPP) in archaea, bacteria, and eukarya. To complement previous biochemical, genetic, and structural studies of this phylogenetically widespread RNA domain, we have characterized its interaction with TPP by isothermal titration calorimetry ...

    The thi-box riboswitch regulates gene expression in response to the intracellular concentration of thiamine pyrophosphate (TPP) in archaea, bacteria, and eukarya. To complement previous biochemical, genetic, and structural studies of this phylogenetically widespread RNA domain, we have characterized its interaction with TPP by isothermal titration calorimetry. This shows that TPP binding is highly dependent on Mg(2+) concentration. The dissociation constant decreases from approximately 200 nM at 0.5 mM Mg(2+) concentration to approximately 9 nM at 2.5 mM Mg(2+) concentration. Binding is enthalpically driven, but the unfavorable entropy of binding decreases as Mg(2+) concentration rises, suggesting that divalent cations serve to pre-organize the RNA. Mutagenesis, biochemical analysis, and a new crystal structure of the riboswitch suggest that a critical element that participates in organizing the riboswitch structure is the tertiary interaction formed between the P3 and L5 regions. This tertiary contact is distant from the TPP binding site, but calorimetric analysis reveals that even subtle mutations in L5 can have readily detectable effects on TPP binding. The thermodynamic signatures of these mutations, namely decreased favorable enthalpy of binding and small effects on entropy of binding, are consistent with the P3-L5 association contributing allosterically to TPP-induced compaction of the RNA.


    Organizational Affiliation

    Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195, USA.



Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
U1 small nuclear ribonucleoprotein AA, B, C, D96Homo sapiensMutation(s): 2 
Gene Names: SNRPAU1A protein
UniProt & NIH Common Fund Data Resources
Find proteins for P09012 (Homo sapiens)
Explore P09012 
Go to UniProtKB:  P09012
PHAROS:  P09012
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsLengthOrganismImage
RNA (87-MER)E, F87N/A
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.10 Å
  • R-Value Free: 0.279 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.25α = 90
b = 71.6β = 94.62
c = 128.35γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
CNSrefinement
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-12-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance