While gasoline may fuel our cars and electricity run our lights, adenosine triphosphate (ATP) provides the energy for all living things. William Brusilow, PhD, associate professor of biochemistry and molecular biology, has a three-year grant from the National Institutes of Health to study how ATP is synthesized. "I’ve developed a genetic and biochemical system for studying energy-coupling, and by energy coupling, I mean the process of connecting the energy of ATP synthesis or hydrolysis to the formation or dissipation of a gradient of ions, in this case, protons," Dr. Brusilow said.
An enzyme known as ATPase can hydrolyze ATP and act as a proton pump, driving the formation of a proton gradient. This same enzyme, acting in the reverse direction as an ATP synthetase, can use the energy of a proton gradient to synthesize ATP.
Dr. Brusilow created functional chimeric ATPase subunits consisting of regions from two different bacterial species -E. coli and B. megaterium. "Basically, it’s a very large-scale mutagenesis--replacing great big chunks of the protein," he said. The chimeric subunits cause a defect in the energy-coupling process when assembled into the enzyme. Now, he is making mutants of the chimeras to both identify the individual amino acids responsible for the defect and to determine how they cause it. "The ultimate goal is to determine, at the molecular level, how one form of energy is coupled to another," said Dr. Brusilow.
Although the value of energy coupling as it relates to health and medicine might not be immediately obvious, Dr. Brusilow points out that ATP synthesis is a vital function of all cells, and defects in energy coupling have been linked to a variety of more well-known problems, including heart disease and cancer.