Detroit Mercy School of Dentistry discovery has major impact

An international research team led by Dr. Eric Krukonis from the University of Detroit Mercy School of Dentistry, unveiled for the first time the atomic configuration of ToxR, a protein bound on the two promoters that govern virulence controlling genes in Vibrio cholerae, the bacterium responsible for cholera.

As cholera continues to threaten public health in regions with disadvantaged living conditions, this groundbreaking discovery could lead towards innovative treatments for the disease.

“The long-term goal of solving this structure, is to identify the molecules that can bind to ToxR and disrupt its ability to bind DNA,” Krukonis said. “Such molecules could then be used as therapeutics to minimize symptoms for people suffering from cholera, while they wait for the infection to be cleared from the body.” 

Krukonis, an associate professor in the division of Integrated Biomedical Sciences and the assistant director of research at the University of Detroit Mercy School of Dentistry, has studied ToxR and its role regulating the virulence gene in Vibrio cholerae for 25 years. Roughly 10 years ago, he initiated a collaboration with protein crystallographer and structural biologist Dr. Miquel Coll in Barcelona, Spain. 

He wanted to work with Coll to solve the structure of ToxR bound to various gene promoters, and test predictions those structures made regarding ToxR function. Krukonis and Coll oftentimes shared their findings via Zoom and Skype. 

“I knew Dr. Coll from his worldwide reputation as an expert in the field of protein/DNA crystallography and structural biology,” Krukonis said. “It has been an eye-opening and fascinating learning experience for me, and a satisfying collaboration.In today’s world, working with scientists from other countries is becoming easier and easier.”

Krukonis’s team worked at the research laboratory at the University of Detroit Mercy School of Dentistry. Members of the team included several students, technicians, and postdoctoral fellows from Krukonis’s laboratory, including Senior Laboratory Technician Dr. Sarah Plecha, Dr. Joshua Thomson, and former ReBUILDetroit Scholar and UDM alumnae, Nour El Yaman. 

In 2018, El Yaman was introduced by Dr. Krukonis to the project of studying virulence gene expression in Vibrio cholerae. She continued developing experiments until the end of her undergraduate career in 2020. She was involved in various intensive research projects associated with dental-related phage biology and bacterial pathogenesis. Her role was to perform biochemical analyses of ToxR-mediated virulence gene regulation and activation in Vibrio cholerae.

“I believe the phenomenal work behind this discovery has put in place the early stages of discovering the mechanism to inhibit the expression of cholera bacterium, and stopping the spread of this infectious disease which has been a threat and major public health issue for many years,” El Yaman said. “The next set of discoveries on the role of ToxR in the cholera toxicity mechanism will set a breakthrough in hopes of change for the better, especially for poor countries lacking a healthy and sanitary lifestyle.” 

Now that the team has the core part of the ToxR DNA structure resolved, Krukonis’s team plans for it to continue its work on ToxR-mediated virulence activation by including more and more molecules in the mix

As they advance in their research, Krukonis stated “the move from “bench side” (laboratory work), to bedside (treatment of patients) is our ultimate goal.”