200 College Street
Final Oral Exam Seminar: Exploring the Specificity and Diversity of Reductive Dehalogenase Enzymes for Improved Bioremediation (Katherine Picott)
When: October 18, 2024 @9:00 – 9:25 a.m.
Place: Wallberg #407
Teams:
Meeting ID: 224 024 752 344
Passcode: iUBk6Z
Abstract:
Industrialization has caused the rapid development and production of organohalide compounds, resulting in their mass contamination in the environment where they are recalcitrant to degradation and pose serious health risks. Bioremediation emerged as a solution to remove chlorinated solvents that contaminate groundwater. The process invokes the activity of the reductive dehalogenase (RDase) enzyme family, which removes halogens from their substrates to ultimately detoxify them. RDases are found in diverse environments, including many anthropogenic waste treatment facilities, but their characterization is dominated by representatives associated with chlorinated solvents, and even these have modest characterization. The primary bottleneck in studying RDases is their production as they have been uncooperative in heterologous expression. This limitation not only slows the study of RDases, but prevents studies that rely on gene manipulation like structure-function investigations and restricts characterization to RDases that express under lab settings.
This work aims to enhance the characterization of the RDase family, addressing both detailed specifics and broader perspectives. First, a system for RDase expression in E. coli is developed by addressing the need for RDases’ two cofactors: cobalamin and iron-sulfur clusters. In co-expressing the RDase with a cobalamin uptake pathway, the active expression of six Dehalobacter RDases was achieved. This system allowed for kinetic and mutagenic studies for highly similar chloroalkane RDases. These comparative studies highlight the nuanced way in which RDases interact with and select their substrates
and identify residues as hot spots for manipulation. Additionally, mining RDases from anthropogenic waste facilities emphasized that the current knowledge of the RDase family is only scratching the surface. The global presence and diversity of RDases reveal an untapped potential for discovering methods to remove the concerning, emerging organohalide contaminants.
Overall, this work provides a comprehensive framework for the characterization of the RDase family and will accelerate our understanding of these enzymes. The findings lay a strong foundation to enable the discovery and design of RDases and advance their application in the removal of persistent contaminants.