Synthesis of an HABA-based affinity matrix for avidin purification from egg white proteins

Abstract

Avidin is a tetrameric protein with a strong and specific interaction with biotin. This protein is an essential tool as a molecular linker in nanobiotechnology. The natural source to purify avidin is egg white. However, its industrial purification is a challenge due to its very low concentration in the feedstock. In this work, an affinity chromatography support based on an azo dye is prepared and characterized. Dye is linked through C-C bound to the Eupergit C matrix by in situ synthesis using anthranilic acid and salicylic acid as building blocks and characterized by different spectroscopies.Avidin is purified from a protein mixture prepared from egg white using the affinity matrix. Ligand density on the solid support modifies avidin recovery and purity degree. In the best condition, avidin is recovered with 74 % purity in one step. In silico studies show that ligand spacer, cysteamine plus dihydroxy propane, was enough for proper Avidin/HABA interaction and also introduces three novel H-bond interactions, restoring the network observed in the avidin/biotin complex.