8SXL

RNA UU template binding to AMP monomer


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.219 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Insight into the structures of unusual base pairs in RNA complexes containing a primer/template/adenosine ligand.

Dantsu, Y.Zhang, Y.Zhang, W.

(2023) RSC Chem Biol 4: 942-951

  • DOI: https://doi.org/10.1039/d3cb00137g
  • Primary Citation of Related Structures:  
    8SWG, 8SWO, 8SX5, 8SX6, 8SXL, 8SY1

  • PubMed Abstract: 

    In the prebiotic RNA world, the self-replication of RNA without enzymes can be achieved through the utilization of 2-aminoimidazole activated nucleotides as efficient substrates. The mechanism of RNA nonenzymatic polymerization has been extensively investigated biophysically and structurally by using the model of an RNA primer/template complex which is bound by the imidazolium-bridged or triphosphate-bridged diguanosine intermediate. However, beyond the realm of the guanosine substrate, the structural insight into how alternative activated nucleotides bind and interact with the RNA primer/template complex remains unexplored, which is important for understanding the low reactivity of adenosine and uridine substrates in RNA primer extension, as well as its relationship with the structures. Here we use crystallography as a method and determine a series of high-resolution structures of RNA primer/template complexes bound by ApppG, a close analog of the dinucleotide intermediate containing adenosine and guanosine. The structures show that ApppG ligands bind to the RNA template through both Watson-Crick and noncanonical base pairs, with the primer 3'-OH group far from the adjacent phosphorus atom of the incoming substrate. The structures indicate that when adenosine is included in the imidazolium-bridged intermediate, the complexes are likely preorganized in a suboptimal conformation, making it difficult for the primer to in-line attack the substrate. Moreover, by co-crystallizing the RNA primer/template with chemically activated adenosine and guanosine monomers, we successfully observe the slow formation of the imidazolium-bridged intermediate (Ap-AI-pG) and the preorganized structure for RNA primer extension. Overall, our studies offer a structural explanation for the slow rate of RNA primer extension when using adenosine-5'-phosphoro-2-aminoimidazolide as a substrate during nonenzymatic polymerization.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Indianapolis IN 46202 USA wz15@iu.edu.


Macromolecules

Find similar nucleic acids by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains LengthOrganismImage
RNA (5'-R(*(TLN)P*(TLN)P*(LCA)P*(LCG)P*AP*CP*UP*UP*AP*AP*GP*UP*CP*U)-3')
A, B
14synthetic construct
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.217 
  • R-Value Observed: 0.219 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.838α = 90
b = 43.838β = 90
c = 82.845γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2023-05-31
    Type: Initial release
  • Version 1.1: 2023-10-25
    Changes: Data collection, Refinement description
  • Version 1.2: 2023-12-13
    Changes: Database references