5KX9 | pdb_00005kx9

Selective Small Molecule Inhibition of the FMN Riboswitch


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 
    0.251 (Depositor), 0.259 (DCC) 
  • R-Value Work: 
    0.216 (Depositor), 0.224 (DCC) 
  • R-Value Observed: 
    0.218 (Depositor) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history

Literature

Atomic resolution mechanistic studies of ribocil: A highly selective unnatural ligand mimic of the E. coli FMN riboswitch.

Howe, J.A.Xiao, L.Fischmann, T.O.Wang, H.Tang, H.Villafania, A.Zhang, R.Barbieri, C.M.Roemer, T.

(2016) RNA Biol 13: 946-954

  • DOI: https://doi.org/10.1080/15476286.2016.1216304
  • Primary Citation Related Structures: 
    5KX9

  • PubMed Abstract: 

    Bacterial riboswitches are non-coding RNA structural elements that direct gene expression in numerous metabolic pathways. The key regulatory roles of riboswitches, and the urgent need for new classes of antibiotics to treat multi-drug resistant bacteria, has led to efforts to develop small-molecules that mimic natural riboswitch ligands to inhibit metabolic pathways and bacterial growth. Recently, we reported the results of a phenotypic screen targeting the riboflavin biosynthesis pathway in the Gram-negative bacteria Escherichia coli that led to the identification of ribocil, a small molecule inhibitor of the flavin mononucleotide (FMN) riboswitch controlling expression of this biosynthetic pathway. Although ribocil is structurally distinct from FMN, ribocil functions as a potent and highly selective synthetic mimic of the natural ligand to repress riboswitch-mediated ribB gene expression and inhibit bacterial growth both in vitro and in vivo. Herein, we expand our analysis of ribocil; including mode of binding in the FMN binding pocket of the riboswitch, mechanisms of resistance and structure-activity relationship guided efforts to generate more potent analogs.


  • Organizational Affiliation
    • a Merck Research Laboratories , Kenilworth , NJ , USA.

Macromolecule Content 

  • Total Structure Weight: 36.3 kDa 
  • Atom Count: 2,359 
  • Modeled Residue Count: 109 
  • Deposited Residue Count: 110 
  • Unique nucleic acid chains: 2

Macromolecules

Find similar nucleic acids by:  (by identity cutoff) 
Entity ID: 1
MoleculeChains LengthOrganismImage
FMN RiboswitchA [auth X]54Fusobacterium nucleatum
Sequence Annotations
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Reference Sequence
Find similar nucleic acids by:  (by identity cutoff) 
Entity ID: 2
MoleculeChains LengthOrganismImage
FMN RiboswitchB [auth Y]56Fusobacterium nucleatum
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
6YG

Query on 6YG



Download:Ideal Coordinates CCD File
J [auth X](6P)-2-{(3S)-1-[(2-methoxypyrimidin-5-yl)methyl]piperidin-3-yl}-6-(thiophen-2-yl)pyrimidin-4-ol
C19 H21 N5 O2 S
NVEPPHORIAFPBH-AWEZNQCLSA-N
K

Query on K



Download:Ideal Coordinates CCD File
C [auth X]
D [auth X]
E [auth X]
F [auth X]
G [auth X]
C [auth X],
D [auth X],
E [auth X],
F [auth X],
G [auth X],
H [auth X],
M [auth Y]
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
MG

Query on MG



Download:Ideal Coordinates CCD File
I [auth X],
K [auth Y],
L [auth Y],
N [auth Y]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free:  0.251 (Depositor), 0.259 (DCC) 
  • R-Value Work:  0.216 (Depositor), 0.224 (DCC) 
  • R-Value Observed: 0.218 (Depositor) 
Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.28α = 90
b = 71.28β = 90
c = 138.93γ = 120
Software Package:
Software NamePurpose
BUSTERrefinement
DENZOdata reduction
SCALEPACKdata scaling
BUSTERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2016-08-24
    Type: Initial release
  • Version 1.1: 2016-09-14
    Changes: Database references
  • Version 1.2: 2016-10-19
    Changes: Database references
  • Version 1.3: 2023-02-22
    Changes: Database references, Derived calculations, Structure summary
  • Version 1.4: 2023-10-25
    Changes: Data collection, Refinement description