title: Beryllium fluoride exchange rate accelerated by Mg²⁺ as discovered by ¹⁹F NMR.
abstract: Beryllium fluoride is widely used as a phosphoryl analogue in macromolecular studies, which are not only fluoride-sensitive but also magnesium-dependent. The beryllium fluorides are a mixture of different species including BeF3(-) and BeF4(2-) exchanging under thermodynamic equilibrium in neutral aqueous solutions. In the cases of mimicking phosphate group transfer, both beryllium fluoride and the magnesium ion are generally needed. However, the impact of magnesium on the bioactivity of beryllium fluoride is not clear. We have found by (19)F NMR spectroscopy that Mg(2+) can severely affect the chemical exchange kinetics between BeF3(-) and BeF4(2-). When the F(-) concentration is relatively low, the presence of 10.0 mM Mg(2+) can accelerate the exchange rate 3-4 fold. However, when the F(-) concentration is relatively high, the Mg(2+) effect on the chemical exchange vanishes. On the basis of these findings, we proposed a possible mechanism that BeF4(2-) and Mg(2+) form an ion pair that affects the distribution of beryllium fluoride species and thus the activity in the solution.
authors.affiliation: Key Laboratory of Magnetic Resonance in Biological Systems, National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences , Wuhan 430071, China.
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Liu
authors.forename: Xi-an
authors.initials: XA
authors.lastname: Mao
authors.forename: Maili
authors.initials: M
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
mesh_terms: D001608:Beryllium / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D005461:Fluorine / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D012015:Reference Standards
chemical_list: D005461:Fluorine; C035982:beryllium fluoride; D008274:Magnesium; D001608:Beryllium; D005459:Fluorides