Contrasting effects of exterior and interior hydrophobic moieties in the complexation of amino acid functionalized gold clusters with α-chymotrypsin

A series Of L-amino acid functionalized gold nanoparticles with oligo(ethylene glycol) (OEG) tethers of varying length are prepared. These studies show that the hydrophobic side chains of amino acids facilitate the structural retention of alpha-chymotrypsin (ChT) but the interior alkyl chains promote its denaturation. An 80-fold range of denaturation rate constants were obtained for ChT in the presence of various nanoparticles. Thus, the tunable denaturation of protein could be achieved by rational combination of amino acid side chains and OEG tethers.