Selected AChE reactivators in different crystalline environment: salts and enzyme

Abstract

The investigation of relationships between the molecular structure of the compounds capable to reactivate acetylcholinesterase (AChE) inhibited by organophosphorus toxins, such as nerve agents and pesticides, is an important step toward synthesis of more efficient antidota. In the present article, we describe the crystal structures of two new AChE reactivators, which are bromides of (E)-1,4-bis(4-hydroxyiminomethylpyridinium)-but-2-ene (K075) and of 4,4′-bis(hydroxyiminomethyl)-1,1′-(1,4-phenylenedimethyl)-bispyridinium (K114). Their molecular geometry and intermolecular interactions in the crystalline state are compared to those in the crystal structures of the well-known AChE reactivators, obidoxime, and TMB-4. Inspection of hydrogen bonds and other short intermolecular contacts in the crystalline AChE–obidoxime complex revealed their similarity to those observed in the crystal structures of K075 and K114.