CHAMPAIGN, Ill. A new technique to study protein dynamics in living cells has been created by a team of University of Illinois scientists, and evidence yielded from the new method indicates that an in vivo environment strongly modulates a protein's stability and folding rate, according to research accepted for publication in the journal Nature Methods and posted on the journal's Web site Feb. 28.
Martin Gruebele, the James R. Eiszner Professor of Chemistry at Illinois and corresponding author of the paper, says the method that he and his team of co-researchers engineered marks the first time anyone has been able to follow the real-time folding and unfolding of proteins outside of a test tube.
"This is the first experiment that allows us to observe the dynamics of a protein folding in a live cell," Gruebele said. "Now we have the capability of looking at how fast biological processes occur as a function of time."
To study the biomolecular dynamics inside of a single living cell, Gruebele and his team pioneered a hybrid method they've dubbed "Fast Relaxation Imaging," a technique that combines fluorescence microscopy and fast temperature jumps.
"It's a tool that combines two worlds: chemical dynamics, and the ability to study reactions as they occur; and biological environments, where cell biologists observe how reactions occur in cells," Gruebele said.
To achieve both a fast upward and downward temperature jump, programmed laser pulses are used to pre-heat, spike, plateau, cool and then finally stabilize the temperature in the cell and its aqueous medium at the final value. An inverted fluorescence microscope is used to observe and record what happens inside the cell, all of which takes place in the span of a few milliseconds.
The cells are usually heated to between 96 and 100 degrees Fahrenheit.
"It's like we give them a little bit of a fever," Gruebele said.
Gruebele says that although temperature jumps have be
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University of Illinois at Urbana-Champaign