Pioneering techniques for identifying large biological molecules such as proteins, carbohydrates and DNA have scooped the Chemistry Nobel prize this year.
John Fenn of Virginia Commonwealth University in Richmond, Virginia, shares half the US$1 million prize with Koichi Tanaka, an engineer at Shimadzu Corporation in Kyoto, Japan. The other half goes to Kurt W眉thrich, professor of biophysics at the Swiss Federal Institute of Technoloy in Zurich.
Now routinely used in labs everywhere to develop new drugs and analyse how our cells work, the trio鈥檚 techniques enriched biology with new 鈥渕icroscopes鈥� to peer at the inner workings of life itself.
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鈥淭he methods have revolutionised the development of new pharmaceuticals,鈥� says the Nobel citation. 鈥淩esearchers can now rapidly and simply reveal what different proteins a sample contains.鈥�
Previously, the same techniques had only worked with small molecules. The winners extended them to reveal the workings of the monster molecules of biology.
Smashed and charged
In the late 1980s, Fenn and Tanaka independently developed a new form of mass spectrometry (MS), a method of analysis used for decades to identify relatively simple molecules.
It works by smashing a molecule into fragments, which become charged. By recording the trajectories of each charged fragment though a combination of electric and magnetic fields, chemists can work out the mass of each one. By piecing together the masses of the fragments, they can identify the original molecule before it was smashed up.
Fenn extended the procedure to solutions of big molecules by developing a technique called electrospray ionisation. He pioneered a way of gradually evaporating all the water molecules from huge proteins until just the hovering protein ion was left. This gentler approach enabled biologists to identify large molecules with MS for the first time.
At the same time, Tanaka developed a technique called soft laser desorption, which blasted big molecules into fragments with lasers.
Join-the-dots
Like the other winners, W眉thrich refined a long-used technique. He modified nuclear magnetic resonance (NMR) so that for the first time it would work with biological molecules.
Unlike mass spectrometry, which simply identifies molecules, NMR reveals the chemical structure of a known molecule. This provides vital information about how proteins work in our bodies and how enzymes catalyse vital reactions, which help us digest our food, for example.
W眉thrich developed a way of working out the structure by focusing the NMR analysis on specific points in the molecule, then connecting them up like a 鈥渏oin-the-dots鈥� puzzle.