We show 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. Interest in L-carnosine dipeptide is compounded by its antioxidant and antitumoral properties further enhanced when combined with D-trehalose. Potentiometric, calorimetric, UV/CD spectroscopic measurements show that copper(II) dimer of D-trehalose-L-carnosine is more stable than the D-trehalose-D-carnosine diastereoisomeric copper(II) dimer (logβL– logβD= 3.6). Free energy calculations highlight that the cause of this different behavior lies on different intramolecular weak interactions between the diastereoisomers. The different pattern of hydrogen bonds and the different CH-π interactions between the π electron-rich imidazole and the α-glucose rings are more favorable of 5 kcal mol-1 in the L-dimer.
Explaining the stereoselectivity of glycopeptide copper(II) dimers by free energy calculations.
Pietropaolo A;
2011-01-01
Abstract
We show 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. Interest in L-carnosine dipeptide is compounded by its antioxidant and antitumoral properties further enhanced when combined with D-trehalose. Potentiometric, calorimetric, UV/CD spectroscopic measurements show that copper(II) dimer of D-trehalose-L-carnosine is more stable than the D-trehalose-D-carnosine diastereoisomeric copper(II) dimer (logβL– logβD= 3.6). Free energy calculations highlight that the cause of this different behavior lies on different intramolecular weak interactions between the diastereoisomers. The different pattern of hydrogen bonds and the different CH-π interactions between the π electron-rich imidazole and the α-glucose rings are more favorable of 5 kcal mol-1 in the L-dimer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
