Carbonate complexation of Mn2+ in the aqueous phase: redox behavior and ligand binding modes by electrochemistry and EPR spectroscopy.

ABSTRACT: The chemical speciation of Mn2+ within cells is critical for its transport, availability, and redox properties. Herein we investigate the redox behavior and complexation equilibria of Mn2+ in aqueous solutions of bicarbonate by voltammetry and electron paramagnetic resonance (EPR) spectroscopy and discuss the implications for the uptake of Mn2+ by mangano-cluster enzymes such as photosystem II (PSII). Both the electrochemical reduction of Mn2+ to Mn0 at an Hg electrode and EPR (in the absence of a polarizing electrode) revealed the formation of 1:1 and 1:2 Mn-(bi)carbonate complexes as a function of Mn2+ and bicarbonate concentrations. Pulsed EPR spectroscopy, including ENDOR, ESEEM, and 2D-HYSCORE, were used to probe the hyperfine couplings to 1H and 13C nuclei of the ligand(s) bound to M

SUBMITTER: Dasgupta J 

PROVIDER: S-EPMC2597525 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature