Final Technical Report

The biochemistry of bacterial proteins involved in redox transformations of metals and minerals is, without dispute, an important area of research. Nevertheless, most studies on bacterial metal transformation have focused not on biochemistry but on genetics and genomics. The objective of this research is to better understand the role of conformation change in electron transfer from cytochromes to minerals, a process that underpins respiratory metal reduction by bacteria in nature and in bioremediation strategies, including reductive immobilization of radioactive contaminants. Our DOE-funded work is specifically focused on answering long-standing questions about the biochemical behavior of these very interesting proteins, and our findings thus far have already made impacts in the fields of environmental microbiology and biogeochemistry. Among the key findings from the project are 1) Successful large-scale production of biomass for protein isolation; 2) Purification of several c-type cytochromes for biochemical study; 3) Characterization of these proteins using spectrophotometric and electrochemical techniques; 4) Examination of protein conformational change and redox activity towards metal oxides using a small mass cytochrome c from Acidiphilium cryptum; 5) Proteomic characterization of A. cryptum biofilms; 6) Training of 2 undergraduate research assistants; 7) Publications and several meeting presentations