title: NMR and theoretical study on the coordination and solution structures of the interaction between diperoxovanadate complexes and histidine-like ligands.
abstract: To simulate the types of coordination and solution structures of the active site of haloperoxidases, the interaction systems between diperoxovanadate complexes [OV(O2)2L]n- (n = 1 or 3, L = oxalate or H2O) and a series of histidine-like ligands in solution have been studied by using 1D multinuclear (1H, 13C, and 51V) NMR, 2D diffusion ordered spectroscopy, and variable-temperature NMR in 0.15 mol/L NaCl ionic medium, representing the physiological conditions of human blood. Some direct NMR data are given for the first time. The reactivity among the histidine-like ligands is imidazole > 2-methylimidazole > carnosine approximately 4-methylimidazole > histidine. Competitive coordination interactions result in a series of new peroxovanadate species [OV(O2)2L']- (L' = histidine-like ligands). When the ligands are 4-methylimidazole, histidine, and carnosine, a pair of isomers have been observed, which are attributed to different types of coordination between vanadium atom and ligands. The results of density functional theory calculations provided a reasonable explanation on the relative reactivity of the histidine-like ligands and the molar ratios of isomers. Theoretical results signify the importance of the solvation effect for the reactivity and stability of the interaction systems.
authors.affiliation: Departments of Physics and Chemistry, State Key Laboratory of Physical Chemistry of Solid Surface, Xiamen University, Xiamen 361005, P.R. China.
authors.forename: Xian-Yong
authors.initials: XY
authors.lastname: Yu
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Cai
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
mesh_terms: D006639:Histidine / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D015394:Molecular Structure; D010545:Peroxides / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013237:Stereoisomerism; D014638:Vanadates / Q000737:chemistry*
chemical_list: D008024:Ligands; D010545:Peroxides; D012996:Solutions; C091767:diperoxovanadate; D014638:Vanadates; D006639:Histidine