Stabilization of AIMP1/p43 and EMAP II recombinant proteins in the complexes with polysaccharide dextran-70

Protein-based pharmaceuticals are among the fastest growing categories of therapeutic agents in the clinic and as commercial products, and typically target high-impact areas such as various cancers, autoimmune diseases and metabolic disorders. The aim of our work was to explore the possibility of reducing the level of aggregation and improve the stability of the recombinant proteins AIMP1/p43 (aminoacyl-tRNA synthetase complex component of the higher eukaryotes) and antitumor cytokine EMAP II (proteolytic cleavage product of AIMP1/p43) in combination with dextran-70 polysaccharide for structural-functional research and development of new sustainable biomedical products.

We studied interaction strength between these recombinant proteins with polymer by fluorescence spectroscopy and molecular docking.

During experimental studies, optimal concentration ratio of AIMP1/p43 and EMAP II recombinant proteins with dextran-70 in which proteins bind to ligand and form complex was established. As a result of molecular docking investigations, spatial structure of the AIMP1/p43-dextran-70 and EMAP II-dextran-70 complexes was obtained and their binding energy was evaluation.

The effect of temperature increase on the stability of these two complexes was determined by fluorescence spectroscopy method. It was found that dextran-70 specifically connects with recombinant proteins. Binding stoichiometry of dextran-70 with protein is about 1:1, which confirms the formation of a specific complex.