1H NMR Relaxation and NOESY in l-Tyrosine in the Presence of Gold Nanoparticles of Different Shapes

In this work, we investigate the effect of gold nanoparticles of different shapes on the structural and dynamic properties of l-tyrosine in aqueous solution. Using ¹H NMR spectroscopy, NOESY, and ¹H NMR relaxation methods, we studied the interactions between l-tyrosine and gold nanoparticles of spherical shaped, star shaped, and rod shaped focusing on their effects on the molecular conformation. Particular attention was paid to the extent to which particles of different shapes affect the structural and dynamic properties of the l-tyrosine molecule. Based on the ¹H NMR spectroscopy data, T₁ relaxation studies, and NOESY cross-peak intensities, we conclude that gold nanoparticles of different shapes exert diverse effects on conformational behavior of the l-tyrosine in aqueous solution. Different changes in interproton distances were found depending on the nanoparticle shape. The presence of nanoparticles in an aqueous l-tyrosine solution induces a reorientation of the –CH₂–CH–COOH chain relative to the aromatic ring. Understanding the processes of conformational changes in AST under the influence of AuNPs, as well as the role of their functional groups binding to AuNPs, has important practical applications for the development of therapeutic agents against Alzheimer’s and Parkinson’s and cardiovascular deceases, associated with aggregation processes and its inhibition.