Enlarge / To the left, a protein is shown with the sort of resolution possible in the early days of electron microscope work.

As you transition to the right, the resolution changes to what’s possible with present-day techniques. (credit: Royal Swedish Academy of Sciences)
The highest possible resolution we can get in a typical image is limited by the wavelength of the light we’re using.

Although there are some clever ways around this limit, one alternative has been to use something with a smaller wavelength.

That “something” turns out to be electrons, and the electron microscope has provided a glimpse of the details inside cells, showing us how their parts are ordered and structured.
But this year’s Nobel Prize in Chemistry went to a group of individuals who pushed the electron microscope to its very limit, figuring out how to use it to determine the position of every single atom in large, complex molecules.

The award goes partly to a researcher who successfully used electron microscopes to image proteins.

But it also goes to two people who developed some of the techniques to make the whole thing work: figuring out how to freeze water quickly enough that it formed a glass and developing an algorithm that could take a large collection of random data and convert it into a coherent picture.
Imaging molecules
For years, understanding the structure of a complex molecule like a protein or RNA involved a technique called X-ray crystallography.

As its name implies, this works by shooting X-rays through crystals of the molecule in question.

But there’s a pretty major limitation to this technique: your molecule has to form a crystal. Not all proteins do.
In fact, some rather important classes of proteins completely refuse to do so, like the ones that are embedded in a cell’s membrane.
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