College of Science

Pierce receives $419K NSF grant to study 'workload' of enzymes and train students in scientific communication

A chemist at The University of Texas at Arlington will use a National Science Foundation grant to investigate the relevant structural factors influencing the extent of biological oxidations catalyzed by a widespread class of iron-containing enzymes.

Brad Pierce, an associate professor of chemistry and biochemistry, received a three-year, $419,400 grant from the NSF Division of Chemistry for his project, titled "Monooxygenase/arylamine N-oxygenase activity within a single non-heme diiron enzyme (MiaE)".

The project provides an opportunity to better understand structural factors driving biological oxidations and thus provide a framework for the rational design of biologically-inspired or bioengineered oxidation catalysts, Pierce said.

"The practical aspects of this work are that we are establishing what features regulate how much 'work' can be performed by an enzyme of this class." he said.

The enzymes which will be utilized in this research are known as non-heme diiron oxidase and/or oxygenases. The type of chemical reaction enabled by these enzymes is called oxidation, which results in a net transfer of electrons from the initial molecule to molecular oxygen, Pierce explained. Non-heme diiron enzymes are a ubiquitous family of enzymes capable of catalyzing a large diversity of biological oxidations.

"Broadly speaking, you can think about the number of electrons transferred in an oxidation reaction as 'work performed', something analogous to carrying a heavy object up a flight of stairs," Pierce said. "For example, many enzymes of this class can carry a load up two steps; these can perform a 2-electron oxidation. Somewhat less common are those enzymes that can carry a load up four steps, or perform a 4-electron oxidation, thus doing more work.

"An entirely new class of enzymes has been identified which can carry a load up six steps. This group is very rare and is poorly characterized. In our work, we've discovered that by making a single structural change to an enzyme which normally performs a 2-step oxidation, we can convert it into one that performs a 6-step reaction. In this analogy, a single point mutation essentially triples the amount of 'work' performed by this enzyme. To my knowledge, this has not been previously demonstrated for any enzyme performing oxidation chemistry."

Pierce says that while the focus of the research will be on a specific class of biological enzymes, in reality, "oxidation reactions" are very common and have tremendous application both biologically and in industrial applications.

"Long term, these findings could potentially be used as a benchmark for the design of biomimetic or industrial catalysts where the amount of 'work' performed can be tailored to any specific need," Pierce said. "Currently, no such catalysts exist."

Each proposal for NSF funding must include a broader impact statement, such as teaching components or plans to increase the number of underrepresented minorities and women in STEM fields. The broader impact proposal for Pierce's project includes training and practical experience in scientific communication for the students involved.

"The reviewers of my proposal felt that this was quite novel and especially timely given our current political climate," he said.

Brad Pierce
"What I proposed was to include elements into my traditional chemistry training program to develop students' ability to communicate science to the general public. While some researchers and faculty are naturally better at this than others, there is no formal 'scientific communication' training included as part of our undergraduate or graduate curriculum, or any other to my knowledge.

"Historically, we focus only on training students how to write and communicate to their academic peers. It has been argued that this absence of communication between scientist and the general public significantly contributes to the decreasing 'scientific literacy' of our society. However, a more practical outcome is that improving student effectiveness in communication will likely have a positive impact on their job prospects, regardless of their ultimate career path."

Fred MacDonnell, professor and chair of the UTA Department of Chemistry & Biochemistry, said that Pierce's project has exciting implications for use in industrial settings and noted the significance of trainings students in how to communicate effectively with a broad audience about their scientific work.

"This research is a cross between classical enzyme mechanics and engineering enzyme mechanics and could lead to whole new ways of using enzymatic catalysis for chemical synthesis," MacDonnell said. "The scientific communication component of Dr. Pierce's project is an intriguing and important effort, as we need to train young scientists to convey important scientific results to non-scientists in a manner that does not confuse, belittle, or otherwise alienate them, but instead includes them in the discussion. This is unfortunately not always the case with scientists."

Pierce received a B.S. in Chemistry from California State University, Chico, in 1996 and a Ph.D. in Chemistry from Carnegie Mellon University in 2003. From 2004-08, he worked as a NIH NRSA postdoctoral fellow at the University of Wisconsin-Madison. He joined the UTA Department of Chemistry and Biochemistry in 2008. He received the UTA President's Award for Excellence in Teaching in 2013.

Posted August 21, 2017