Going nano to see viruses 3-D
'Technical tour de force' is first step to seeing proteins in 3-D
Physicists have created an MRI-like machine capable of making three-dimensional scans of single virus particles — a resolution 100 million times higher than previously possible.
The achievement is a step toward imaging individual proteins, the knotted molecules that assemble to form viruses and that play a central role in the chemistry of all life.
“Our long-term dream is to have a technique that could look at the 3-D structure of molecules in your body such as proteins,” says Daniel Rugar, a physicist with IBM Research at Almaden Research Center in San Jose, Calif. Currently, finding proteins’ 3-D shapes requires first crystallizing the proteins, a difficult and time-consuming step that hinders protein research. Rugar’s MRI-like technique, reported online January 12 in Proceedings of the National Academy of Sciences, might someday image individual particles without the need for crystallization.
Like MRI machines used in hospitals, the new technique depends on a phenomenon called nuclear magnetic resonance, or NMR — the ability of a strong magnetic field to make atoms’ magnetic spin axes line up like little compasses pointing north. However, the new method differs from hospital MRI machines in how it senses this effect.