Modulation of aldose reductase inhibition by halogen bond tuning

ACS Chem Biol. 2013 Nov 15;8(11):2484-92. doi: 10.1021/cb400526n. Epub 2013 Sep 17.


In this paper, we studied a designed series of aldose reductase (AR) inhibitors. The series was derived from a known AR binder, which had previously been shown to form a halogen bond between its bromine atom and the oxygen atom of the Thr-113 side chain of AR. In the series, the strength of the halogen bond was modulated by two factors, namely bromine-iodine substitution and the fluorination of the aromatic ring in several positions. The role of the single halogen bond in AR-ligand binding was elucidated by advanced binding free energy calculations involving the semiempirical quantum chemical Hamiltonian. The results were complemented with ultrahigh-resolution X-ray crystallography and IC50 measurements. All of the AR inhibitors studied were shown by X-ray crystallography to bind in an identical manner. Further, it was demonstrated that it was possible to decrease the IC50 value by about 1 order of magnitude by tuning the strength of the halogen bond by a monoatomic substitution. The calculations revealed that the protein-ligand interaction energy increased upon the substitution of iodine for bromine or upon the addition of electron-withdrawing fluorine atoms to the ring. However, the effect on the binding affinity was found to be more complex due to the change of the solvation/desolvation properties within the ligand series. The study shows that it is possible to modulate the strength of a halogen bond in a protein-ligand complex as was designed based on the previous studies of low-molecular-weight complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehyde Reductase / antagonists & inhibitors
  • Aldehyde Reductase / chemistry*
  • Computer Simulation
  • Crystallography, X-Ray
  • Enzyme Inhibitors / chemistry
  • Halogens / chemistry*
  • Hydrogen Bonding
  • Inhibitory Concentration 50
  • Models, Molecular


  • Enzyme Inhibitors
  • Halogens
  • Aldehyde Reductase