When proteins, antibodies and other biological molecules kiss, a new kind of biosenso...( When biological molecules kiss a new...)

When biological molecules kiss, a new kind of biosensor can tell.

A new and deceptively simple technique has been developed by chemists at Vanderbilt University that can measure the interactions between free-floating, unlabeled biological molecules including proteins, sugars, antibodies, DNA and RNA.

That is precisely the kind of capability needed to capitalize on the new avenues of research that have been opened up by the 15-year-plus effort to sequence the human genome. DNA is the blueprint of all living creatures. But, just as the blueprint of a building is much simpler than the actual structure, so too DNA is far simpler than the myriad of molecules that make up living bodies. As a result, scientists need powerful new methods to study the actual behavior of all these molecules, particularly how they work together.

The new method is called back-scattering interferometry (BSI). By shining a red laser like those used in barcode scanners into a microscopic, liquid-filled chamber where two kinds of molecules are mixed, the instrument can measure the strength with which they react, even when the interactions are extremely weak. In fact, the researchers have demonstrated that it is sensitive enough to detect the process of protein folding, they report in the Sept. 21, 2007 issue of the journal Science.

Molecular interactions are the very heart of biology, says Professor of Chemistry Darryl J. Bornhop, who headed the 12-year development process.

Pharmaceuticals depend on reactions between proteins and small molecules or between pairs of proteins or between interactions between RNA and DNA or pairs of DNA molecules. So the ability to measure how that happens is very advantageous.

The members of the Bornhop research team are post doctoral students Joey Latham and Dmitry Markov; graduate student Amanda Kussrow; Henrik Sorenson, who is now at the Ris National Laboratory in Denmark; and Senior Research Associate Richard Jones.

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