title: Intramolecular weak interactions in the thermodynamic stereoselectivity of copper(II) complexes with carnosine-trehalose conjugates.
abstract: 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 β(L)(22-2) - log β(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-π interactions between the π-electron-rich imidazole and the α-glucose rings are more favorable by 5 kcal mol(-1) in the L dimer.
authors: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, 6 Viale A. Doria, 95125 Catania, Italy.
authors: Giuseppa I
authors: GI
authors: Grasso
authors: Giuseppe
authors: G
authors: Arena
authors: Francesco
authors: F
authors: Bellia
authors: Giuseppe
authors: G
authors: Maccarrone
authors: Michele
authors: M
authors: Parrinello
authors: Adriana
authors: A
authors: Pietropaolo
authors: Graziella
authors: G
authors: Vecchio
authors: Enrico
authors: E
authors: Rizzarelli
mesh_terms: D002336:Carnosine / Q000737:chemistry* / Q000378:metabolism; D002625:Chemistry, Organic; D003300:Copper / Q000737:chemistry / Q000378:metabolism; D004151:Dipeptides / Q000737:chemistry; D006001:Glycoconjugates / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D011522:Protons; D013237:Stereoisomerism; D013816:Thermodynamics; D014199:Trehalose / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004151:Dipeptides; D006001:Glycoconjugates; D007093:Imidazoles; D011522:Protons; D003300:Copper; C029899:imidazole; D002336:Carnosine; D014199:Trehalose