To visualize the zinc-proton cycle, Case Western Reserve scientists used sophisticated dynamic imaging technology the cellular cycle operates on time scales comparable to the blink of the eye. Dynamic imaging involved a labeling system x-ray-mediated hydroxyl radical footprinting that recognizes water molecules in transmembrane proteins. The scientists also used mass spectrometry, a powerful atom-and-molecule recognition technology, to study the labeled proteins. These technologies allowed investigators to watch the YiiP protein in real time as it took up zinc atoms and rearranged its structure cycle through a pumping sequence.
"Membrane proteins (including CDF) are some of the most important cellular drug targets, including G-protein coupled receptors (GPCR), which represent 50 percent of the non-antibiotic drug market." Chance said.
GPCRs are protein molecules that sense chemical signals outside the cell and then activate cellular responses to these signals. Chance and his colleagues have studied GPCR structure and dynamics using innovative mass spectrometry-based technology. In this more recent work on CDFs, a dynamic picture of the membrane protein has emerged. It is a complex, but explainable, machine that uses a widely available form of energy, the proton gradient, to carry out cellular functions.
"We have now produced high-resolution pictures of signal transmission and ion transport mechanisms for a range of ion channels and GPCRs," Chance said. "Our work in CDFs is a visible example of the power of these new technologies to solve important problems in the membrane protein field. We must continue to examine CDFs to understand their
|Contact: Jeannette Spalding|
Case Western Reserve University