Scientists capture three-dimensional image of a virus

The New York Times (1/13, D3, Markoff) reports, "For the first time, researchers at an IBM laboratory have captured a three-dimensional image of" a "tobacco mosaic virus." The "technique used by the" scientists working at the Almaden Research Center "has some similarity to magnetic resonance imaging, or MRI., now routinely used by physicians to peer inside the human body." But according to paper appearing online Jan. 12 in The Proceedings of the National Academy of Sciences, "the results were 100 million times better in terms of resolution with the new technique, magnetic resonance force microscopy, or MRFM." The breakthrough may "be of interest to structural biologists who are trying to unravel the structure and the interactions of proteins."

Proteins "are giant jumbles of amino acids shaped like a tangle of curled ribbons and crimped strings," Forbes (1/12, Fahey) explained. "How they are built and shaped determines whether they can help digest a bite of steak au poivre or play a role in crippling a flu virus." In short, the "beautiful, messy collection of proteins in our bodies are made from a mere 20 amino acids," but "figuring out what intricate shape they take, or 'seeing' their structures" was "hard," until now.

Physicist Daniel Rugar and his team created a "MRI-like machine" that "senses the mechanical push and pull of the viruses' atoms on a microscopic cantilever arm," Science News (1/13, Barry) reports. During their experiment, the "researchers placed the virus particles on the tip of the arm and positioned the tip close to a strong, tiny, fixed magnet," and "as the magnetic spin axes of the hydrogen atoms in the viruses flipped up and down, the atoms were alternately attracted to and repelled by the fixed magnet, thus creating the pushing and pulling on the arm." Eventually, the "strength of these forces indicated how many hydrogen atoms were at a given spot in the virus, and moving the tip around built up a 3-D representation of the virus shape." The Scientist (1/12, Ghose) also covered the breakthrough in its NewsBlog.