Multifrequency EPR studies of manganese catalases provide a complete description of proteinaceous nitrogen coordination.

ABSTRACT: Pulse electron paramagnetic resonance (EPR) spectroscopy is employed at two very different excitation frequencies, 9.77 and 30.67 GHz, in the study of the nitrogen coordination environment of the Mn(III)Mn(IV) state of the dimanganese-containing catalases from Lactobacillus plantarum and Thermus thermophilus. Consistent with previous studies, the lower-frequency results reveal one unique histidine nitrogen-Mn cluster interaction. For the first time, a second, more strongly hyperfine-coupled (14)N atom is unambiguously observed through the use of higher frequency/higher field EPR spectroscopy. The low excitation frequency spectral features are rationalized as arising from the interaction of a histidine nitrogen that is bound to the Mn(IV) ion, and the higher excitation frequency features ar

SUBMITTER: Stich TA 

PROVIDER: S-EPMC3418057 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature