Optical and NMR Spectroscopy Studies on Manganese Superoxide Dismutase

from Vibro alginolyticus


Hui-chu Hsieh, T. K. S. Kumar and Chin Yu

Department of chemisty, National Tsing Hua University, Hsinchu,


Superoxide Dismutase ( SODs) are metalloproteins that catalyze the conversion of superoxide anions to peroxide and molecular oxygen. SODs have been classified into three groups according to the metal ions bound at the active site: Cu/Zn, Fe or Mn. The Mn and Fe enzymes are structural relatives and Mn and Fe SOD occur as dimers or tetramers. In the present study, we have expressed a Mn-SOD from Vibro alginolyticus in E. coli.. The expressed protein was purified in high yield by nicked affinity chromatography. Gelfiltration and Sedimation Equilibrium experiments suggest that the protein prefers to exist in a dimeric state. Far UV circular dichroism spectra reveals that the backbone of the protein is predominantly helical. The thermodynamic stability of the protein has been investigated based on chemical denaturant induced unfolding. In addition, structural features of the protein are probed by using multidimensional NMR technique. These results would be presented in detail.