engleski

Chemisorptions of bacterial receptors for hydrophobic amino acids and sugars on gold for biosensor applications: a surface plasmon resonance study of genetically engineered proteins

This paper demonstrates potential applications of two periplasmic receptor proteins from E. coli as sensing elements for biosensors using the surface plasmon resonance (SPR) technique. These molecules, namely the aspartate to cysteine mutant of the D-glucose/D-galactose receptor (LS-DIC) and the glutamine to cysteine mutant of the D-glucose/D-galactose receptor (GGR-Q26C) proteins, are chemisorbed on a thin (~40 nm) Au film in neutral K2HPO4 buffers. Using angle and time resolved SPR measurements, we show that the adsoption behaviors of both proteins are dominated by diffusion-free second order Langmuir kinetics. We also show that the protein-modified Au films exhibit measurable SPR shifts upon binding to their respective target ligands. According to these SPR data, the kinetics of ligand binding for both LS-DIC and GGR-Q26C are governed by an irreversible first order diffusion limited Langmuir model. The utility of the SPR technique for studying reactions of biological molecules is further illustrated in this work.

bacterial receptor; gold; surface plasmon resonance

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