Industrial use of oxochlorine species (ClOx-) has led to high concentrations of perchlorate, chlorate, and chlorite as contaminates in the environment. Certain proteobacteria have evolved to survive under these conditions utilizing a perchlorate respiratory pathway. In this pathway perchlorate reductase catalyzes the reduction of perchlorate and chlorate to toxic chlorite. The last step in this pathway uses a heme enzyme called chlorite dismutase (Cld) to catalyze the decomposition of chlorite to chloride anion and molecular oxygen. This formation of an O-O bond is rare in nature with photosystem II being the only other well characterized example. Chlorite dismutases are also found in nonperchlorate-respiring proteobacteria. We present the chlorite decomposing activity and efficiency of Cld from  Klebsiella pneumoniae, a nonperchlorate-respiring bacterium. The heme environment of the KpCld has been characterized by UV-Visible and resonance Raman spectroscopy. These spectroscopic results combined with the kinetics are used to gain insight into the structural basis of function in KpCld. Analysis of these results and the comparable data for the Cld of Dechloromonas aromatica, a perchlorate-respiring bacterium, will be discussed in terms of structural characteristics of optimum chlorite decomposition activity.

Investigation of mechanism of the heme enzyme chlorite dismutase from <i>Klebsiella pneumoniae</i>

247th National Meeting (2014)

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Investigation of mechanism of the heme enzyme chlorite dismutase from Klebsiella pneumoniae