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Out of the Freezer

A visit with Gavin King, Assistant Professor of Physics, Joint Assistant Professor of Biochemistry

By Kyle Burton
Published: - Topics: ultrastable atomic force microscope biology physics biochemistry

“What does it mean to see an object?” Gavin King’s question at first seems philosophical. During last year’s Biophysics and Your Body summer program, King’s collaborators posed a task for a group of middle school students: determine the contents of a shoebox without opening it. The students were given some materials and left to their creative wills.

“I thought they would just go in with their skewers from the vertical orientation. That’s what I did.” He chuckles. “But some of them were actually quite clever, because they went in from the top, and then from the sides. I thought that was neat because that’s basically a CAT scan.” The rudimentary ‘imaging’ creates a full picture of the box’s contents. King says the activity sparked a discussion about the nature of what it is we see. King smiles as he quotes one student, “‘Oh, I think I can see an atom.’ Really? What does it mean to see an atom?”

Gavin King’s work at the University of Missouri is all about seeing; as Assistant Professor of Physics and, jointly, Biochemistry, he applies the tools of observation in physics to biological specimens. He currently works with atomic force microscopy, which can zoom in to extreme fractions of a nanometer.

King has spent much of his time at the University of Missouri trying to “push his field, biophysics, ‘out of the freezer.’” King and his team analyze proteins that exist on the membranes that define cells. Traditionally, high precision measurement scientists prefer to work in colder temperatures because the cold slows molecules. The slower the molecules, the more stable the measurement.

King, however, examines membrane proteins in a near real-world status: room temperature water. The warmer room temperature keeps membrane proteins “happy,” he says, and a happy protein is an active protein, demonstrating real-world behavior they wish to study. However, a warm environment allows the instrument and the sample to drift (known as “thermal drift”), which compromises the accuracy of the imaging.

Formerly, the solution to thermal drift on an atomic force microscope was to “shoot fast,” taking micro-snapshots of samples as quickly as possible. Instead of a smooth imaging, scientists settled for stop-motion photographs of a molecule whose location was ever unpredictable. The disparity between the result and the desired result was congruent with the difference in animation techniques between Wallace and Gromit and Toy Story.

How, then, to lock the microscope onto the sample? “As part of my postdoctoral work I came up with a technique to actually do this. We came up with a strategy to use focused laser beams—one to scatter off the tip which reads the sample, another focused laser beam that scatters off the sample—and we use this pair of focused laser beams and the scattered light fields that they produce to stabilize the tip with respect to the sample.” Because of thermal drift, recapturing an active protein in a previous state had been impossible. King’s Ultra Stable Atomic Force Microscope not only dials into the protein’s speed, but its laser tracking system allows researchers to observe the sample at any point they choose.

King designs and assembles the microscope himself. The MU Physics Machine Shop makes the parts—except for a certain adhesive King prefers: Silly Putty. “That’s high tech,” he says humorously, showing off his laser-equipped AFM. “It’s actually very effective for dampening vibrations traveling through cords. It’s a little hard to get off, though.”

Coaxing his fellow scientists out of the freezer requires more than just new techniques. “Scientists as a whole—and of course there’s always exceptions to this—tend to be sort of aloof people,” King says. “You can be a very good scientist…but you don’t do much favor in terms of the scientific effort as a whole by staying in your lab all day.” Rather, King believes the scientific community must proactively reach out to the general public. He adds, “the scientific effort as a whole requires investment from people who are not scientists.”

King actively engages in such outreach. Aside from his university teaching, King collaborated with other faculty last year to start “Biophysics and Your Body,” which includes the aforementioned science summer camp as well as interdisciplinary curricula—on ears, eyes, muscles, energy, metabolism—designed for middle school teachers to infuse into their classrooms. Recalling his own science education, he says, “It’s pretty sad that physics was taught one year, biology was taught the next, chemistry was taught the next, and there was absolutely no overlap. But it’s all interrelated, of course.”

Professor King's instrument rack for his atomic force microscopeIn the King Laboratory, even the lab’s Instrument Rack (pictured left), an “Honorary Member” of the team, escapes pigeonholing: “Not really a person, but it is six feet tall!” King’s affability and facile knowledge help blur boundaries—physics, biology; man, electrical cord cluster. His middle schoolers may have outwitted him at thinking outside the box in order to get into the (shoe)box. But this would seem his point—now, to go in from the top, and then from the sides, and then from the bottom. What does it mean to see an object? It means to step out of the cold and, like his Ultra Stable Atomic Force Microscope, move right along with the thing, viewing it exactly as it is.