3GC5

tRNA-guanine transglycosylase in complex with 6-amino-4-(2-aminoethyl)-2-(methylamino)-1,7-dihydro-8H-imidazo[4,5-g]quinazolin-8-one


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.4 Å
  • R-Value Free: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

How to Replace the Residual Solvation Shell of Polar Active Site Residues to Achieve Nanomolar Inhibition of tRNA-Guanine Transglycosylase

Ritschel, T.Kohler, P.C.Neudert, G.Heine, A.Diederich, F.Klebe, G.

(2009) Chemmedchem 4: 2012-2023

  • DOI: 10.1002/cmdc.200900343
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • In a computational and structural study, we investigated a series of 4-substituted lin-benzoguanines that are potent inhibitors of tRNA-guanine transglycosylase (TGT), a putative target for the treatment of shigellosis. At first glance, it appears se ...

    In a computational and structural study, we investigated a series of 4-substituted lin-benzoguanines that are potent inhibitors of tRNA-guanine transglycosylase (TGT), a putative target for the treatment of shigellosis. At first glance, it appears self-evident that the placement of a positively charged ligand functional group between the carboxylate groups of two adjacent aspartate residues in the glycosylase catalytic center leads to enhanced ligand binding. The concomitant displacement of water molecules that partially solvate the aspartates prior to ligand binding appears to result as a consequence of this. However, the case study presented herein shows that this premise is much too superficial. Placement of a likely positively charged amino group at such a pivotal position, interfering with the residual water solvation shell, is at best cost-neutral compared with the unsubstituted parent ligand not conflicting with the residual water shell. A ligand that orients a hydroxy group in this position shows even decreased binding. Based on the cost-neutral placement of the amino functionality, hydrophobic side chains can now be further attached to fill, with increasing potency, a small hydrophobic pocket remote to the aspartates. Any attempts to cross the pivotal position between both aspartates with nonpolar scaffolds reveals only decreased binding, even though the waters of the residual solvation shell are successfully repelled. This surprising observation fostered a detailed analysis of the role of water molecules involved in the residual solvation of polar active site residues. Their geometry and putative replacement in the binding pocket of TGT has been studied by a comparative database analysis, computational active site mapping, and a series of crystal structure analyses. Furthermore, conformational preferences of attached hydrophobic moieties explain their contribution to a gradual increase in binding affinity.


    Organizational Affiliation

    Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35032 Marburg, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Queuine tRNA-ribosyltransferase
A
386Zymomonas mobilis subsp. mobilis (strain ATCC 31821 / ZM4 / CP4)Mutation(s): 0 
Gene Names: tgt
EC: 2.4.2.29
Find proteins for P28720 (Zymomonas mobilis subsp. mobilis (strain ATCC 31821 / ZM4 / CP4))
Go to UniProtKB:  P28720
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
2MQ
Query on 2MQ

Download SDF File 
Download CCD File 
A
6-amino-4-(2-aminoethyl)-2-(methylamino)-1,7-dihydro-8H-imidazo[4,5-g]quinazolin-8-one
C12 H15 N7 O
GERXMHCMTFTAGY-UHFFFAOYSA-N
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
2MQKi: 55 nM BINDINGMOAD
2MQKi: 55 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.4 Å
  • R-Value Free: 0.192 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 90.200α = 90.00
b = 65.000β = 96.20
c = 70.800γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
HKL-2000data scaling
SHELXL-97refinement
CNSrefinement
MxCuBEdata collection
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-12-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Non-polymer description, Version format compliance