The reason for this heterogeneity is that proteins have to thread their way through whatever channel happens to be available, Gruebele said. And, as opposed to the expansive environment of a test tube, there's a lot of cellular furniture for proteins to bump into in living cells.
"You have a very simple, very homogenous environment when you study proteins in vitro," he said. "In a living cell, 30 to 40 percent of the contents are solids of some kind. There are big ones, like ribosomes, and walls, like cell membranes, all the way down to very small parts like other proteins or sugars. So there's really a huge distribution of all these different sizes that a protein has to wend its way around that may hinder it from freely expanding and contracting, as it would do when it unfolds and refolds in an artificial environment.
"So it's the environment, and not just an intrinsic property of the protein, that causes all these variations that we observed."
In addition to revealing the inner working of cell dynamics, Gruebele, who is also a researcher at the Beckman Institute, says Fast Relaxation Imaging will have practical, human-scale applications as well.
"With this new technique, we now have the capability of looking at how fast biological processes occur as a function of time, including potentially interesting disease processes, especially with neurological disorders and diseases that cause dementia such as Alzheimer's, Huntington's, CreutzfeldtJakob disease," he said.
There's also the potential to induce disease processes, and study the dynamics of those processes in a live animal study.
"We can take these proteins that cause these diseases, actually put them into the kind of cells where they cause these diseases, give them a hea
|Contact: Phil Ciciora|
University of Illinois at Urbana-Champaign