CHAMPAIGN, Ill. According to new research, old ideas about water behavior are all wet.
Ubiquitous on Earth, water also has been found in comets, on Mars and in molecular clouds in interstellar space. Now, scientists say this common fluid is not as well understood as we thought.
"Water, as we know it, does not exist within our bodies," said Martin Gruebele, a William H. and Janet Lycan Professor of Chemistry at the University of Illinois. "Water in our bodies has different physical properties from ordinary bulk water, because of the presence of proteins and other biomolecules. Proteins change the properties of water to perform particular tasks in different parts of our cells."
Consisting of two hydrogen atoms and one oxygen atom, water molecules are by far the body's largest component, constituting about 75 percent of body volume. When bound to proteins, water molecules participate in a carefully choreographed ballet that permits the proteins to fold into their functional, native states. This delicate dance is essential to life.
"While it is well known that water plays an important role in the folding process, we usually only look at the motion of the protein," said Gruebele, who also is the director of the U. of I.'s Center for Biophysics and Computational Biology, and a researcher at the Beckman Institute. "This is the first time we've been able to look at the motion of water molecules during the folding process."
Using a technique called terahertz absorption spectroscopy, Gruebele and his collaborator Martina Havenith at the Ruhr-University Bochum studied the motions of a protein on a picosecond time scale (a picosecond is 1 trillionth of a second).
The technique, which uses ultrashort laser pulses, also allowed the researchers to study the motions of nearby water molecules as the protein folded into its native state.
The researchers present their findings in a paper published July 23 in the online version of the chemistry journa
|Contact: James E. Kloeppel|
University of Illinois at Urbana-Champaign