Thursday December 06 2007
CEA
The Relationship between the Manganese(II) Zero-Field Interaction and Mn(II)/Mn(III) Redox Potential of Mn(4'-X-terpy)2 Complexes.
J Am Chem Soc (2007), 129, 13825-13827.
CEA
How esoteric EPR spectroscopy measurements can tell us about how proteins work?
Recently, we have been studying a seemingly esoteric topic, the zero-field interactions in manganese(II) ions, specifically in manganese/iron superoxide dimutases (SOD). These proteins have very high degree of structural homology, but their chemistry is highly specific: iron SODs work only with iron, manganese SODs with only manganese while the so-called “cambialitsic” SODs are active with either. High-field electron paramagnetic resonance (HFEPR) spectroscopy can distinguish the three SOD types based on their Mn(II) zero-field interactions. Until now we did not understand what the physical basis was for difference in the zero-field interaction was. Our current paper describes a study on a series of synthetic Mn(II) complexes that involved HFEPR, electrochemical measurements and quantum chemical calculations. We showed that the Mn(II) zero-field interaction is related to charges around the Mn(II) ion and, most intriguingly, can be correlated to the reduction potential of the Mn(II), a quantity that is of fundamental importance to the chemistry of SODs.
Gätjens J, Sjödin M, Pecoraro VL, Un S. (2007). The relationship between the manganese(II) zero-field interaction and Mn(II)/Mn(III) redox potential of Mn(4'-X-terpy)2 complexes. J Am Chem Soc, 129 (45), 13825-13827.