6UC9

Guanine riboswitch bound to O6-cyclohexylmethyl guanine

  • Classification: RNA
  • Organism(s): Bacillus subtilis
  • Mutation(s): No 

  • Deposited: 2019-09-15 Released: 2020-07-22 
  • Deposition Author(s): Matyjasik, M.M., Batey, R.T.
  • Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.94 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.189 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.1 of the entry. See complete history


Literature

High Affinity Binding of N2-Modified Guanine Derivatives Significantly Disrupts the Ligand Binding Pocket of the Guanine Riboswitch.

Matyjasik, M.M.Hall, S.D.Batey, R.T.

(2020) Molecules 25

  • DOI: https://doi.org/10.3390/molecules25102295
  • Primary Citation of Related Structures:  
    6UBU, 6UC7, 6UC8, 6UC9

  • PubMed Abstract: 

    Riboswitches are important model systems for the development of approaches to search for RNA-targeting therapeutics. A principal challenge in finding compounds that target riboswitches is that the effector ligand is typically almost completely encapsulated by the RNA, which severely limits the chemical space that can be explored. Efforts to find compounds that bind the guanine/adenine class of riboswitches with a high affinity have in part focused on purines modified at the C6 and C2 positions. These studies have revealed compounds that have low to sub-micromolar affinity and, in a few cases, have antimicrobial activity. To further understand how these compounds interact with the guanine riboswitch, we have performed an integrated structural and functional analysis of representative guanine derivatives with modifications at the C8, C6 and C2 positions. Our data indicate that while modifications of guanine at the C6 position are generally unfavorable, modifications at the C8 and C2 positions yield compounds that rival guanine with respect to binding affinity. Surprisingly, C2-modified guanines such as N 2-acetylguanine completely disrupt a key Watson-Crick pairing interaction between the ligand and RNA. These compounds, which also modulate transcriptional termination as efficiently as guanine, open up a significant new chemical space of guanine modifications in the search for antimicrobial agents that target purine riboswitches.


  • Organizational Affiliation

    Department of Biochemistry, University of Colorado, Boulder, Colorado, CO 80309, USA.


Macromolecules
Find similar nucleic acids by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains LengthOrganismImage
Guanine riboswitchA [auth B]67Bacillus subtilis
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CMG (Subject of Investigation/LOI)
Query on CMG

Download Ideal Coordinates CCD File 
J [auth B]6-O-CYCLOHEXYLMETHYL GUANINE
C12 H17 N5 O
MWGXGTJJAOZBNW-UHFFFAOYSA-N
NCO
Query on NCO

Download Ideal Coordinates CCD File 
B
C [auth B]
D [auth B]
E [auth B]
F [auth B]
B,
C [auth B],
D [auth B],
E [auth B],
F [auth B],
G [auth B],
H [auth B]
COBALT HEXAMMINE(III)
Co H18 N6
DYLMFCCYOUSRTK-UHFFFAOYSA-N
ACT
Query on ACT

Download Ideal Coordinates CCD File 
I [auth B]ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.94 Å
  • R-Value Free: 0.211 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 133.468α = 90
b = 35.171β = 91.55
c = 41.889γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-3000data reduction
HKL-3000data scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR01-GM073850

Revision History  (Full details and data files)

  • Version 1.0: 2020-07-22
    Type: Initial release
  • Version 1.1: 2023-10-11
    Changes: Data collection, Database references, Refinement description