[Structural mechanisms of interaction of cyanoacrylates with plant tubulin]

Structural mechanisms underlying the specific binding of cyanoacrylate compounds with tubulin of higher plants have been studied by example of interaction of ethyl-(2Z)-3-amino-2-cyano-4-ethylhex-2-enoate (CA1) and isopropyl-(2Z)-3-amino-2-cyano-4-ethylhex-2-enoate (CA2) with Arabidopsis thaliana alpha-tubulin. It was revealed that the cyano group of cyanoacrylates is a functional analog of the nitrile group, which determines the processes of specific interaction with plant tubulin for dinitroaniline compounds. Based on the data of spatial structure fluctuations, dynamics of hydrogen bonds and interaction energy of the CA1 and CA2, the most probable binding mode for these compounds with plant alpha-tubulin was identified and appropriate site of interaction was characterized. Seven out of 10 residues composing this site (Gln-133, Asn-249, Val-250, Asp-251, Val-252, Asn-253 and Glu-254) are obligatory components of the dinitroanilines' binding site on the plant alpha-tubulin surface. Thus, the binding site on the alpha-tubulin surface characterized by us is able to recognize and specifically bind the substances which are cardinally different by their chemical nature and have no common pharmacophore groups, under the condition of a certain similarity of their electrostatic topology.