Study on short peptide ligands binding to insulin receptors by quantum dots labeling

摘要

The important and complex physiological action of insulin depends on its binding to insulin receptor(IR).Recently,phage display is used to generate surrogate peptides that define the hotspots involved in protein-protein interaction between insulin and IR.We took the Chinese hamster ovary cells over-expressing insulin reseptors(CHO-IR)as targets to select peptide ligands of IR from a phage display random hexapepide library.Assayed with cell-ELISA,we found five peptide ligands could compete for insulin binding and have Kd values in the micromolar range.In addition,the positive phage clones and the five peptide ligands conjugated with QDs can specifically label the CHOIR,and the binding affinities between peptide ligands and IR can be seen clearly by imaging.The QD labeling method is consistent compared with the result of ELISA assay.QDs have emerged as a new class of potential and promising fluorescent probe for many biomedical applications,especially for protein signaling and cell imaging,and our study have explored the application of QDs in characterizing the short peptide insulin analogs.