The Interactions Of Gold Nanoparticles With Biomolecules

Gold nanoparticles, including nanocrystals and nanoclusters, exhibit great potentials in various biomedical fields, such as delivery, diagnostic, and therapeutic agents. In order to improve their suspension stability, the gold nanoparticles are often protected with various coatings, e.g. alkanethiol, DNA and peptides. Such coatings can also improve the biocompatibility of gold nanoparticle and modulate the surface properties of gold nanoparticle. Recently, peptide-protected gold nanoparticles have attained growing interests. Such gold nanoparticles possess remarkable biocompatibility. Moreover, the peptide coating can endow gold nanoparticle with additional function. For example, the gold nanoparticle conjugated with targeting peptide sequence can specifically bind to the disease-related protein, serving as the molecular probe for diagnosis. Besides, conjugated peptide can facilitate the transportation of gold nanoparticle through membraneThis work studied the structure of Au25 cluster coated by nine tridecapeptides, together with its interaction with thioredoxin reductase 1(Trx R1), by using molecular dynamics simulation. Firstly, a 200 ns MD simulation wass performed to investigate the structural of peptide-coated Au NC in solution. Both radius of gyration and root-mean-square deviation of Au NC were calculated to characterize the distribution and structure of peptides on the surface of Au NC. Then, 5 independent simulations, each with at least 50 ns, were performed to study the possible binding of Au NC to Trx R1 and investigate the possible binding mode of Au NC. A representative binding process was chosen to study the binding process of Au NC to Trx R1. This work used the center of mass(COM) distance between Au25 core of Au NC and Cys497, Sec498 of the active site of Trx R1, together with the number of contact atoms between Au NC and Trx R1 to study the stability and specificity of the binding process. In addition, the binding process of Au NC to Trx R1 was also researched by the molecular docking method.