Abstract

For the purpose of proteins bio-conjugation to Gold Nano-Particles (GNPs), we designed and synthesized a polypeptide named NanoLock, derived from SNARE (Soluble NSF Attachment protein REceptor) proteins and able to form a remarkably stable complex with the SNARE protein SNAP25 (Synaptosome Associated Protein of 25 kDa). We also characterized the adsorption of a SNAP25 recombinant fusion to Glutathione S-Transferases (GST) named GST-SNAP25 onto GNPs and found that it forms a stable protein corona surrounding GNPs. Using GST-SNAP25 as an intermediate protein, passively adsorbed on GNPs, we were able to stably bind NanoLock to GNPs.

By fusing an arbitrary protein of interest to the affinity tag NanoLock, it would be in principle possible to bind any protein to GST-SNAP25 coated GNPs by simple mixing, in a site-oriented way. Therefore, we propose the pair NanoLock/GST-SNAP25 as a universal tool for the easy bio-conjugation of recombinant proteins to GNPs and possibly other gold surfaces. Further engineered versions of SNAP25, able to bind surfaces other than gold, could be used to decorate with proteins other materials, taking advantage of the same modular approach of the system described here in the case of GNPs.