Life is movement, and now we can finally see it.
For generations, science has captured proteins in stillness — precise, frozen, and incomplete. Researchers at the University of Regensburg have now crossed a long-standing threshold, combining nuclear magnetic resonance spectroscopy with molecular dynamics simulations to render the invisible motions of the RNA exosome visible for the first time. In doing so, they have not merely solved a technical puzzle but reframed a foundational question: to understand how life's molecular machines work, we must learn to watch them move.
- Structural biology has long been limited to frozen snapshots — beautiful maps of proteins at rest, but silent on how those proteins actually function in motion.
- The RNA exosome, a ten-protein complex essential to RNA degradation in every living cell, had resisted dynamic study because its size made it inaccessible to existing NMR and simulation techniques.
- By pairing NMR spectroscopy with molecular dynamics simulations in a novel combination, the Regensburg team unlocked atomic-level motion data in a complex previously considered too large for either method alone.
- The exosome moves at radically different speeds — some regions shifting billions of times per second, others only thirty — and the slower movements appear to be the ones that actually drive RNA degradation.
- The approach now opens a path toward studying other large molecular machines across cellular life, transforming static structural images into continuous, high-resolution films of biological function.
For decades, scientists have mapped proteins with extraordinary precision — cataloging every atom, every bond, every architectural detail. But a protein at rest is not a protein at work, and the gap between structure and function has remained one of biology's most stubborn blind spots. Researchers at the University of Regensburg have now found a way to close it.
The team, led by biophysicists Till Rudack and Remco Sprangers, focused on the RNA exosome — a ten-protein complex responsible for degrading RNA, a routine and essential task in every living cell. Scientists could already see what the exosome looked like when frozen in time. What they could not see was how it moved, and without that, they could not fully understand how it worked.
The breakthrough came from pairing two techniques that had never been successfully combined at this scale. NMR spectroscopy measures how individual atoms vibrate and interact within a protein; molecular dynamics simulations translate that data into visual models of motion. Each method had limits when used alone — NMR typically struggled with large complexes like the exosome — but together they created something new: a continuous record of molecular transformation with atomic-level detail.
What emerged was a landscape of motion operating at vastly different speeds. Some regions of the exosome shift billions of times per second; others move only about thirty times per second. It is those slower movements that appear most significant — one region in particular moves at roughly the same pace as the exosome degrades RNA itself, suggesting the machine must flex to function.
The implications extend well beyond this single complex. The same combined approach could be applied to the molecular machines that assemble DNA, transport cargo through cells, or carry signals across an organism — each of which performs its work through precise structural change. For the first time, scientists have a reliable method to watch that choreography unfold in real time.
For decades, scientists have photographed proteins in stillness. They've mapped the architecture of molecular machines with extraordinary precision, cataloging every atom in place. But a protein at rest is not a protein at work. The real story—how these machines actually function, how they bend and shift and dance through the chemical choreography of life—has remained largely invisible. Now, researchers at the University of Regensburg have found a way to make that invisible motion visible.
The team, led by biophysicists Till Rudack and Remco Sprangers alongside postdocs Jobst Liebau and Daniela Lazzaretti, has captured what amounts to a molecular film of the RNA exosome in action. The exosome is a ten-protein complex that degrades RNA—a routine but essential task in every living cell. For years, scientists could see what the exosome looked like when frozen in time, thanks to cryo-electron microscopy and other structural tools. What they couldn't see was how it moved, and that gap in understanding meant they couldn't fully grasp how it actually worked.
The breakthrough came from combining two techniques that had never been successfully paired at this scale. Nuclear magnetic resonance spectroscopy, or NMR, measures how individual atoms vibrate and interact within a protein. Molecular dynamics simulations use computers to calculate what those atomic movements mean—to translate abstract data into visual models. Separately, each method had limits. NMR typically worked only on small proteins; larger complexes like the exosome were too unwieldy. But together, the two approaches created something new: a window into motion that had previously been invisible to every other method.
What they saw was a landscape of movement operating at wildly different speeds. Some regions of the exosome move billions of times per second—so fast they blur into near-invisibility. Other parts move far more slowly, only about thirty times per second. It's those slower movements that appear to matter most. The researchers identified one particular region that moves at roughly the same pace as the exosome degrades RNA itself. The connection isn't yet proven, but the correlation is striking: without that movement, there would be no degradation. The machine needs to flex to function.
This is more than a technical achievement, though it is that. The team has essentially transformed the way structural biology works. Instead of static snapshots—the protein in configuration A, the protein in configuration B—they now have a continuous record of transformation. They can watch the exosome do its job in real time, or rather, in simulated real time, with atomic-level detail. Regions that were previously invisible to all other methods are now measurable and analyzable. The short-lived interactions between RNA and the exosome, fleeting events that happen and vanish in microseconds, can now be studied.
The implications ripple outward. This same combination of NMR and molecular simulation could be applied to other large protein complexes—the molecular machines that assemble DNA, transport cargo through cells, or relay signals from one part of an organism to another. Each of these machines performs its function through motion, through the precise choreography of structural change. For the first time, scientists have a reliable way to watch that choreography unfold. What was once frozen in place can now be seen in motion, and in that motion lies the true story of how life works.
Notable Quotes
To truly understand the function of proteins, we need to understand how they move and how their structure changes when they perform their function.— Prof. Dr. Remco Sprangers, University of Regensburg
The combination of NMR and MD works analogously to a microscope with very high spatial and temporal resolution and provides a kind of movie of the atomic interaction of proteins.— Prof. Dr. Till Rudack, University of Regensburg
The Hearth Conversation Another angle on the story
Why does it matter that we can see proteins moving? We already knew they moved—we just couldn't see it.
There's a difference between knowing something happens and understanding how it happens. Knowing the exosome degrades RNA is one thing. Seeing which parts move, at what speed, and in what sequence—that's the difference between a description and an explanation.
So this is about proving causation? That the movement causes the degradation?
Not quite proving it yet, but finding the correlation. They saw a part of the exosome moving at the same speed as RNA gets degraded. That's a clue. Without the ability to measure that motion, you'd never even know to look for the connection.
What makes this technique different from just watching a protein under a microscope?
A microscope shows you what's there at one moment. This gives you a continuous record—a movie. And it works at the atomic level, which no microscope can do. You're seeing individual atoms vibrating and interacting, not just the overall shape.
Why couldn't they do this before?
NMR works by measuring how atoms respond to magnetic fields, but with large complexes, the signal gets too noisy, too many atoms interfering with each other. They needed a way to extract meaning from that noise. The molecular simulations do that—they take the raw NMR data and calculate what it actually means in terms of movement.
Is this just useful for RNA degradation, or does it apply more broadly?
It applies to any large protein complex. Any molecular machine that works by changing shape. That's most of them. This opens a door that was locked before.
What happens next?
Other labs will start using this approach on other complexes. And the Regensburg team will keep refining it, probably looking deeper into how the exosome's movements actually enable RNA degradation. The static picture of the cell is becoming a moving picture.