The Study On The Interaction Between Part Peptides Of BSA And AP-Gold Nanoparticles With Fluorescence Resonance Energy Transfer

New researches show Bovine Serum Albumin (BSA) with high affinity adsorption to amphiphilic polymer coated aqueous phase gold nanoparticles (AP-AuNPs). After proteinase-K digestion, Sodium Dodecyl Sulfate (SDS) elution, polyacrylamide gel electrophoresis (PAGE) purification, recycling and mass spectrometry, we found that adsorption zone of BSA with AP-AuNPs is three polypeptides, LGEYGFQNALIVRY, KDAFLGSFLYEYSR and KVPQVSTPTLVEVSRS. In order to further study the action mechanism of BSA and AP-AuNPs, we selected two polypeptides from the three polypeptides which contain fluorescent amino acid residues, LGEYGFQNALIVRY (P1 and KDAFLGSFLYEYSR (P2), and one polypeptide FDEHVKLVNELTEF (P3), the furthest polypeptide away from the adsorption zone. Firstly, three polypeptides were synthesized with the method of solid-phase polypeptide synthesis in vitro and mixed with AP-AuNPs, respectively. By maximum absorbance spectroscopic redshift and agarose identification methods, we made a qualitative research on the interaction between three polypeptides and AP-AuNPs. Besides, with the methods of fluorescence resonance energy transfer and thermodynamic equation, we can calculate binding constants and Gibbs free energy of AP-AuNPs and three polypeptides. By comparing the binding constants and Gibbs free energy, we found that, AP-AuNPs can adsorb P1 and P2, not adsorb P3 or the adsorption force is tiny. Finally, a certain recognition to adsorption zone of BSA, AP-AuNPs can specific bind to portion peptides of BSA, which is related to polypeptides sequence information. These results lead us have a deeper level of understanding to the action mechanism of BSA and AP-AuNPs, which possesses important guidance significance to some hot topics, such as protein biomarkers with nanoparticles, heavy metal pollution detection and the development of polypeptides which have the ability to identify.