Microbial redox reactions of inorganic sulfur compounds play a vital role in balancing the turnover of this element in the environment. These vital reactions are carried out by the enzyme system encoded by the sox operon. The central player of the sulfur oxidation biochemistry is the SoxY-Z protein complex. Another protein called SoxF having sulfide dehydrogenase activity has the ability to reactivate the inactivated SoxY-Z protein complex. This SoxF protein is obtained from the sox operon of Chlorobium tepidium. In the present work an attempt has been made to understand the structural details of the activity of SoxF protein. A plausible biochemical mechanism has been predicted regarding the involvement of the SoxF protein in biological sulfur anion oxidation process. Since this is the first report regarding the structural biology of SoxF protein this study may shed light in the hitherto unknown molecular biochemistry of sulfur anion oxidation by sox operon. (C) 2011 Elsevier Inc. All rights reserved.