Gold Nanoflower for Selective Detection of Single Arginine Effect in α-helix Conformational Change over Lysine in 310-helix Peptide

Hydroxylamine based growth reaction in presence of natural L-amino acids (9 mM) and gold nanoparticle seed mostly produce aggregated or non-aggregated gold nanostructures except the cases of immediate precipitation with aspartic acid, glutamic acid, cysteine and tyrosine. Among the other amino acids, arginine shows the control growth reaction to form gold nanoflower from gold nanoparticle seeds, which have been pre-incubated with amine modified DNA (NH2-oln). The absorbance trend with NH2-oln in presence of arginine is similar to the aggregation behavior in presence of histidine and methionine. The formations of gold nanoflower with arginine and aggregation due to histidine and methionine in presence of NH2-oln have been sorted out with lower concentration (50 μM) of these amino acids. This observation has been successfully transferred to differentiate 310-helical Ac-(AAAAK)3A-NH2 from α-helical Ac-(AAAAR)3A-NH2. The concept has been further applied for the detection of single arginine modification closes...