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Elucidating the Binding Mechanism of a Novel Silica-Binding Peptide

Year: 2020

Journal: Biomolecules, Volume 10, JAN

Authors: Bansal, Rachit; Elgundi, Zehra; Care, Andrew; Goodchild, Sophia C.; Lord, Megan S.; Rodger, Alison; Sunna, Anwar

Keywords: solid-binding peptides (SBPs); linker-protein G (LPG); surface plasmon resonance (SPR); quartz crystal microbalance with dissipation monitoring (QCM-D); circular dichroism (CD) spectrometry; equilibrium dissociation constant (K-D)

Linker-protein G (LPG) is a bifunctional fusion protein composed of a solid-binding peptide (SBP, referred as the linker) with high affinity to silica-based compounds and a Streptococcus protein G (PG), which binds antibodies. The binding mechanisms of LPG to silica-based materials was studied using different biophysical techniques and compared to that of PG without the linker. LPG displayed high binding affinity to a silica surface (K-D = 34.77 +/- 11.8 nM), with a vertical orientation, in comparison to parent PG, which exhibited no measurable binding affinity. Incorporation of the linker in the fusion protein, LPG, had no effect on the antibody-binding function of PG, which retained its secondary structure and displayed no alteration of its chemical stability. The LPG system provided a milder, easier, and faster affinity-driven immobilization of antibodies to inorganic surfaces when compared to traditional chemical coupling techniques.