ORGN 690 |
| Monolayer-protected nanoparticles feature tunable size, surface functionality and core materials, providing versatile scaffolds for targeting biomacromolecules. In this work, various amino acid-functionalized gold nanoparticles have been fabricated to recognize the surface of α-chymotrypsin. Gel electrophoresis and activity assays confirm that the complex formation is predominated by surface complementary electrostatic interaction between nanoparticles and the enzyme. Meanwhile, the complex stability constants are found to be correlated with the hydrophobicity index of amino acid side chains, indicating that hydrophobic interactions also assist in the complex formation. Time-course fluorescence and circular dichroism studies reveal that the protein at the nanoparticle surface experiences different levels of denaturation. The denaturation rate contants are correlated to the hydrophobicity of amino acid side chains as well as the length of oligo(ethylene glycol) tethers in the ligands. Furthermore, the catalytic behavior of α-chymotrypsin toward cationic, neutral and anionic substrates is modulated by the presence of amino acid-functionalized gold nanoparticles. The amino acid monolayer on the nanoparticle is proposed to control both the capture of substrate by the active site and the release of product through electrostatic interaction, leading to enhanced substrate specificities. |
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Asymmetric Reactions, Combinatorial Chemistry, Molecular Recognition and Self-Assembly, Proteins, Peptides, Amino Acids and Enzyme Inhibitors
8:00 PM-10:00 PM, Wednesday, March 28, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Organic Chemistry |