Intramolecular weak interactions in the thermodynamic stereoselectivity of copper(II) complexes with carnosine-trehalose conjugates(655 views) Grasso GI, Arena G, Bellia F, Maccarrone G, Parrinello M, Pietropaolo A, Vecchio G, Rizzarelli E
Dipartimento di Scienze Chimiche, Universita degli Studi di Catania, 6 Viale A. Doria, 95125 Catania, Italy.
Computational Science Department of Chemistry and Applied Biosciences, ETH Zurich, USI-Campus, 6900 Lugano, Switzerland
References: Not available.
Intramolecular weak interactions in the thermodynamic stereoselectivity of copper(II) complexes with carnosine-trehalose conjugates
The interactions of metal ions with chiral molecules are of particular interest for relevant biochemical processes, as many of them are made possible only with a selected chirality of the stereocenters. In this work we report a study of the stereoselectivity of copper(II) complexes with D-trehalose-L-carnosine and D-trehalose-D-carnosine as a prototypical case of natural chirality selection. The interest in L-carnosine dipeptide is compounded by its antioxidant and antitumor properties, which are further enhanced when combined with D-trehalose. Potentiometric, calorimetric, and UV/circular dichroism (CD) spectroscopic measurements show that the copper(II) dimer of D-trehalose-L-carnosine is more stable than the D-trehalose-D-carnosine diastereoisomeric copper(II) dimer (log beta(L)(22-2) - log beta(D)(22-2) = 3.6). Free-energy calculations highlight that the cause of this different behavior lies with different intramolecular weak interactions between the diastereoisomers. The different pattern of hydrogen bonds and the different CH-pi interactions between the pi-electron-rich imidazole and the alpha-glucose rings are more favorable by 5 kcal mol(-1) in the L dimer. Copyright 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Intramolecular weak interactions in the thermodynamic stereoselectivity of copper(II) complexes with carnosine-trehalose conjugates