Miniature magnets, big questions
It’s a summer day in Seattle unlike any other – the clear blue skies go on for miles above you, the sun embraces you in a hug that provides just the right amount of warmth on your skin, and despite being in a city, everywhere you look you see varying shades of green. You decide what could be a better way to start the day than taking your kiddo for a walk through one of the city’s many expansive parks. But it’s not long after you arrive that your tranquil walk becomes an interrogation by your kid: How do plants eat? Why are some plants big and some small, why are they different colors? What happens to plants in your belly if you eat them?! Every question is as important as the one that came before it and they all need answering.
Many of us have experienced the seemingly endless curiosity of children, but what if I told you that many of these questions have the same one-word answer? Proteins, the small molecules that play crucial roles in all living processes. The weight of our immense, living world is built on the backs of these molecules we cannot even see.
Scientists have been working for decades to continually expand our toolbox for visualizing and understanding proteins. Insight into how proteins function in their seemingly endless list of roles means the chance to not only understand how living processes work but maybe even how to fix them when they don’t.
My work aims to help improve one tool in our kit for studying proteins. We use small magnetic ‘rulers’ to find the distance between various points on a protein by allowing them to hold the magnets. Our magnetic rulers work in much the same way as any old magnet. When you hold two magnets close to one another, you feel them interact and as you move them apart, that interaction fades. By asking our protein to hold the magnets, we can figure out how far apart they are from one another by how strongly the magnets are interacting. Using these measured distances, we can get an idea of what the protein looks like which is often tied to how it carries out its job. To truly understand how a protein works means being able to see it in action, so we measure not just one distance but several as the protein moves from one position to the next.
Children are scientists. Not only because they ask questions but because they keep asking questions like ‘how do you know that?’ even after they get their answers. When we measure distances on our proteins, how do we know to trust what we’re seeing? My work takes what information we already know about the protein and uses statistics to produce thousands of possibilities of what distances we might see based on our hypothesis. Then we can compare this to our data and decide how accurately we have captured parts of the protein’s structure in a given situation. Improving how confident we are about a protein’s structure allows us to make more predictions about how it works and hopefully answer a few more of those how and whys about the world around us.
Sarah Sweger is a Ph.D. student in the Chemistry department at the University of Washington, but Sweger’s work sits at the crossroads between chemistry, biology, and physics. Sweger’s research focuses on utilizing electrons as magnetic “rulers” to understand the structure and function of proteins and how we can use statistics to determine the reliability of our measurements.