Investigating the organohalide dehalogenation respiratory chain of Dehalococcoides mccartyi CBDB1

Organohalide-respiring bacteria (OHRB) are important agents of bioremediation, helping to clean up groundwater contaminated with toxic compounds such as chloroform, perchloroethene (PCE), and chlorobenzene. This metabolic pathway relies on enzymes known as reductive dehalogenase homologs (RdhAs). The mechanisms by which RdhAs reduce organohalides remains elusive, particularly in the case of the Chloroflexi OHRB Dehalococcoides and Dehalogenimonas. These microbes are critical to bioremediation efforts, as they are the only OHRB known to reduce PCE to ethene without accumulation of the toxic intermediate vinyl chloride (VC). Previous work in Dehalococcoides mccartyi CBDB1 has identified seven proteins thought to form a respiratory complex. The goal of this work is to explore the complex further by 1) attempting heterologous expression in E. coli, 2) testing the identity of the proton pump, and 3) determining the number of complexes expressed per cell. Understanding the biochemistry of organohalide respiration will inform OHRB application to contaminated sites, as well as advancing our knowledge of enzyme function and extreme metabolisms.

Faculty Supervisor:

Elizabeth Edwards

Student:

Partner:

Helmholtz-Zentrum für Umweltforschung

Discipline:

Life Sciences

Sector:

Environmental Science and Technology

University:

University of Toronto

Program: