Engineering LacI for Self-Assembly of Inorganic Nanoparticles on DNA Scaffold through the Understanding of LacI Binding to Solid Surfaces
✍ Scribed by Haibin Chen; Xiaodi Su; Koon-Gee Neoh; Woo-Seok Choe
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 555 KB
- Volume
- 19
- Category
- Article
- ISSN
- 1616-301X
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✦ Synopsis
Abstract
The potential of utilizing the DNA binding protein lac repressor (LacI) to organize inorganic nanoparticles (NPs) is explored in this study. A peptide cognitive of both SiO~2~ and TiO~2~ simultaneously (STB1, ‐CHKKPSKSC‐) is genetically engineered into the C‐terminus of LacI to give LacI‐STB1, and the inserted STB1 peptides in the context of LacI‐STB1 molecules are shown to actively interact with both SiO~2~ and TiO~2~. Wild‐type LacI is found to interact with the two surfaces at its flexible N‐terminal DNA binding domain, and LacI‐STB1 exhibits much stronger binding affinity to both surfaces by harnessing a second binding region (STB1 peptide) fused at its C‐terminus. The quantitative analysis of binding kinetics reveals that, compared to wild‐type LacI with one binding region (N‐terminus), two remote binding regions (N‐terminus and C‐terminus) in LacI‐STB1 do not lead to faster adsorption rates to the two surfaces, but remarkably slow down the desorption rates. Finally, using LacI‐STB1 as a linker, the successful assembly of a sandwich nanostructure of DNA/LacI‐STB1/TiO~2~ NPs is demonstrated using surface plasmon resonance (SPR) measurements and TEM. The demonstrated LacI‐STB1‐mediated assembly of TiO~2~ NPs on DNA scaffold may provide a generic platform for controlled spatial arrangement of various nanoparticles of engineering interest.