3EGZ | pdb_00003egz

Crystal structure of an in vitro evolved tetracycline aptamer and artificial riboswitch


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 
    0.260 (Depositor), 0.265 (DCC) 
  • R-Value Work: 
    0.212 (Depositor), 0.219 (DCC) 
  • R-Value Observed: 
    0.217 (Depositor) 

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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history

Literature

Structural basis for specific, high-affinity tetracycline binding by an in vitro evolved aptamer and artificial riboswitch

Xiao, H.Edwards, T.E.Ferre-D'Amare, A.R.

(2008) Chem Biol 15: 1125-1137

  • DOI: https://doi.org/10.1016/j.chembiol.2008.09.004
  • Primary Citation Related Structures: 
    3EGZ

  • PubMed Abstract: 

    The tetracycline aptamer is an in vitro selected RNA that binds to the antibiotic with the highest known affinity of an artificial RNA for a small molecule (Kd approximately 0.8 nM). It is one of few aptamers known to be capable of modulating gene expression in vivo. The 2.2 A resolution cocrystal structure of the aptamer reveals a pseudoknot-like fold formed by tertiary interactions between an 11 nucleotide loop and the minor groove of an irregular helix. Tetracycline binds within this interface as a magnesium ion chelate. The structure, together with previous biochemical and biophysical data, indicates that the aptamer undergoes localized folding concomitant with tetracycline binding. The three-helix junction, h-shaped architecture of this artificial RNA is more complex than those of most aptamers and is reminiscent of the structures of some natural riboswitches.


  • Organizational Affiliation
    • Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA.

Macromolecule Content 

  • Total Structure Weight: 33.25 kDa 
  • Atom Count: 2,298 
  • Modeled Residue Count: 156 
  • Deposited Residue Count: 163 
  • Unique protein chains: 1
  • Unique nucleic acid chains: 1

Macromolecules


Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
U1 small nuclear ribonucleoprotein A98Homo sapiensMutation(s): 2 
Gene Names: SNRPA
UniProt & NIH Common Fund Data Resources
Find proteins for P09012 (Homo sapiens)
Explore P09012 
Go to UniProtKB:  P09012
PHAROS:  P09012
GTEx:  ENSG00000077312 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP09012
Sequence Annotations
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Reference Sequence
Find similar nucleic acids by:  (by identity cutoff) 
Entity ID: 2
MoleculeChains LengthOrganismImage
Tetracycline aptamer and artificial riboswitch65N/A
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CTC

Query on CTC



Download:Ideal Coordinates CCD File
D [auth B]7-CHLOROTETRACYCLINE
C22 H23 Cl N2 O8
CYDMQBQPVICBEU-XRNKAMNCSA-N
MG

Query on MG



Download:Ideal Coordinates CCD File
C [auth A]
E [auth B]
F [auth B]
G [auth B]
H [auth B]
C [auth A],
E [auth B],
F [auth B],
G [auth B],
H [auth B],
I [auth B],
J [auth B],
K [auth B],
L [auth B],
M [auth B],
N [auth B],
O [auth B]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free:  0.260 (Depositor), 0.265 (DCC) 
  • R-Value Work:  0.212 (Depositor), 0.219 (DCC) 
  • R-Value Observed: 0.217 (Depositor) 
Space Group: P 4 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.835α = 90
b = 120.835β = 90
c = 55.279γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SOLVEphasing
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-10-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-10-25
    Changes: Refinement description
  • Version 1.3: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.4: 2024-10-30
    Changes: Data collection, Structure summary