Application Of Surface Plasmon Resonance In The Screening Of Protein A Small Molecule Inhibitors

In this thesis,a Surface Plasmon Resonance(SPR)platform is set to screen small molecule compounds against ligand A(referred as Protein A in the thesis),in order to find a small molecule that can replace polypeptide A(referred as Peptide A).Firstly,through the selection of biosensor chips,interventions for solvent correction,ligand A capture density experiments,and various model fitting experiments the equilibrium dissociation constant between ligand A and polypeptide A was determined to be 20 to 30 nM.Then,we mutated the specific structural loci on ligand A by knocking off 3 amino acids,and identified the specific binding site of ligand A by cross interaction experiments between wild type ligand A,mutant ligand A and a reference protein(referred as Protein B).Finally,SPR was used to screen a small molecule library and to identify compounds with interaction on ligand A to perform competition experiments.A dissociation constant reflecting the inhibition effect(Inhibition K_D)of samples can be determined.The process can also exclude compounds with allosteric effect.From these experiments,one small molecule was fished out from the library that binds specifically to ligand A,with an Inhibition K_D of 450 to 650nM.Few other small molecules were obtained which showed allosteric effects on ligand A.