For more than a quarter century, Partch has lived among the orchestrators of the circadian clock, the proteins whose rise and fall control its workings. As a postdoc, she produced the first visualization of the bound pair of proteins at its heart, CLOCK and BMAL1. Since then, she has continued to make visible the whorls and twists of those and other clock proteins while charting how changes to their structure add or subtract time from the day. Her achievements in pursuit of that knowledge have brought her some of the highest honors in this field of science: the Margaret Oakley Dayhoff Award from the Biophysical Society in 2018, and the National Academy of Sciences Award in Molecular Biology in 2022.

As Partch speaks, her sense of the relentlessness of time — the fact that it changes us, whether we want it to or not — shades her voice with quiet urgency. Her own journey has taken an unexpected turn; at the height of her career, she’s having to step back from the lab bench. In 2020, at the age of 47, she was diagnosed with amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease. On average, people live three to five years after being diagnosed with ALS.

But that has not stopped her from thinking about the clock proteins.

She considers them, her head tilted, the light glinting off her glasses, as we sit in her living room in the hills near Santa Cruz, California. It is noon, about six hours since the sun’s photons propelled CLOCK and BMAL1 into action in her cells and the cells of every human on the West Coast.

In her mind’s eye, she can see the proteins, each a ribbon of amino acids folded around itself. BMAL1 has a kind of waist that CLOCK clasps like a dancer. Each dawn, the pair take up perches on the densely coiled mass of the genome and summon the enzymes that transcribe DNA. Over the course of the day, they cause other proteins to whirl out of the cell’s machinery, including several that eventually eclipse their power. Three proteins find handholds on CLOCK and BMAL1 around 10 p.m., silencing them and stripping them from the genome. The tide of DNA transcription shifts. Finally, in the depths of night, a fourth protein grips a tag on the end of BMAL1 and prevents any further activation.

Seconds turn into minutes, minutes into hours. Time passes. Gradually, the repressive quartet of proteins decays. In the small hours of the morning, CLOCK and BMAL1 are once again being made to renew the cycle.

Every day of your life, this system links the body’s fundamental biology to the movement of the planet. Every day of your life, as long as it lasts. No one understands this more deeply than Partch.

Chemistry and Clocks

The summer before fifth grade, when Partch was 10 years old, her father, who was a carpenter, broke his wrist playing soccer. While he waited for it to heal, he took chemistry at the local community college. He showed her how to balance a chemical equation in their yard outside Seattle, on a chalkboard propped against a tree. That was her introduction to chemistry.

“I still remember thinking how the mathematical precision of chemistry was so cool — very different from the biology we were being taught in school at that age,” she said.

When she recalls her college years at the University of Washington, she admits with a wry chuckle that some of what jumps out are the memories of attending concerts — driving down to Olympia for Sleater-Kinney shows, seeing Mudhoney and Nirvana — and her enjoyment of books by authors like Ursula Le Guin. But she was also entranced by a class on the chemistry of living systems. After graduation, she went to work as a technician at Oregon Health and Science University in Portland. Every day, she fell more in love with research. In 2000, she and her boyfriend, James, a musician and graphic designer, moved to the University of North Carolina, Chapel Hill so she could begin her doctorate.

Soon after she arrived, she met the person who would introduce her to the clock. She took a class with the molecular biologist Aziz Sancar, known for his work on DNA repair. “I was struck by the beautiful precision with which he taught us basic scientific concepts,” she said. “I was like, ‘Dude, this guy is so smart.’” Sancar, who would win a Nobel Prize in 2015, was studying a class of proteins called cryptochromes, which includes the clock proteins CRY1 and CRY2. Every organism from cyanobacteria to redwood trees has a clock, but the proteins driving each system are different. In mammals, the most important proteins aside from CLOCK and BMAL1 are forms of PER and CRY.