How did life on Earth begin? 2023 Schmidt Science Fellow Kira Podolsky grapples with one of science’s biggest questions.

“I like to play in the space between chemistry and biology,” explains Kira Podolsky, whose Fellowship placement is at MIT.

“Earlier in my training, I was asking, ‘how can we use chemicals to build life?’ But with my team at Professor Ronald T. Raines’ lab at MIT, we are also going the other way: biology to chemistry.

“What we’re doing now is asking big questions like, ‘Can cellular life still function on minimal chemical components?’ And what can that tell us about what minimal components might have been like in the origins of life or the last universal common ancestor?”

The last universal common ancestor or LUCA is the hypothesis that, around 4 billion years ago, one ancestral population of cells emerged that went on to evolve into all forms of life, from bacteria to baboons.

But exactly how life on Earth began and gave rise to LUCA is one of the biggest unknowns of science, and it is hotly debated.

Most scientists agree with the theory that life arose gradually from non-living matter, such as organic molecules.

But it is contested whether that organic material came from an extraterrestrial source, such as meteorites falling from space, or whether it was synthesized on the prebiotic earth.

“I like to play in the space between chemistry and biology”- Kira Podolsky.

It’s a fascinating field to be working in, says Kira.

“Answering the big questions is what gets me out of bed in the morning. How was life formed? That’s a pretty big one. It’s a profound mystery and it’s very rewarding to work on it.”

Kira’s interdisciplinary work at MIT focuses on peptides – short chunks of protein consisting of a few amino acids.

She has recently shared her research as a preprint investigating if peptides can replace essential enzymes inside cells.

Enzymes dwarf peptides, both in size and complexity. They are huge proteins that are hundreds of amino acids long.

But Kira’s findings reveal that yeast cells can survive if their essential enzymes are switched for peptides.

If simple peptides can replace some enzyme functions in modern cells, that suggests that early chemistry may not have needed the large, complex proteins that exist in life today.

So these basic peptides likely performed essential functions in the ‘pre-biology’ era, before fully living cells developed.

“This is the first time anybody has shown that a peptide can sustain and facilitate life,” Kira says.

“Our research shows us that even a small peptide catalyst can support life now, which means that peptides could have probably supported life in the past.”

Kira’s background is in chemistry, but with a biological twist.

Pivoting from chemistry to biology for her Schmidt Science Fellows postdoc, was the key to her work.

As a PhD student, in Neal Devaraj’s lab at the University of California, San Diego, she used chemistry to build artificial cells from the bottom up.

But she says she had very little experience with ‘real biology’ before her interdisciplinary Fellowship.

“The pivot definitely expanded my view of this spectrum from chemistry to biology or the space between them.

“Now I can look at these problems, in developing life or in synthetic biology, through the lens of both chemistry and biology,” she says.

Aside from revealing a part of the puzzle of how life began, her peptide discovery could one day provide wider benefits for human health.

“Nature has already evolved enzymes, so this is a case of looking at what biology has already made and then using chemistry to refine that.

“It’s going to be an iterative process where we can make better therapeutics, better drug delivery vehicles, and more stable peptide-based drugs.”

That might include future therapies for neurodegenerative diseases.

The peptide that Kira has been designing is able to structurally change a type of chemical bond called a disulfide bond.

One of the hallmarks of neurodegenerative diseases like Alzheimer’s are tangled, toxic aggregations of protein in the brain, known as plaques.

Disulfide bonds are one type of abnormal chemical cross-link that stabilize these damaging plaques.

By targeting these structural weak points, Kira’s peptides have therapeutic potential for disrupting the plaques, or for preventing them from forming in the first place.

Testament to her groundbreaking research, Kira is a co-winner of the 2026 Stratingh Award for early career researchers and she delivered her award lecture at the Groningen Molecular Chemistry Symposium (GroMoChem) last month.

She was delighted to have been selected as a potential future leader in molecular chemistry and to get the chance to discuss the field’s future with an international audience.

Kira is also receiving MIT’s Department of Chemistry “Chemistry Au-Stars Award” (a play on “all-stars,” using Au, the chemical symbol for gold), which recognizes researchers who demonstrate excellence in their work and exemplify the department’s core values.

Now a Senior Schmidt Science Fellow, Kira will soon be serving the Fellowship community as a Senior Fellow Facilitator, mentoring a small group of current Fellows as part of the Science Leadership Program.

“I really want to give back to the Fellowship because the community has been invaluable to me,” she says.

Community is one of the things that Kira has valued most about her fellowship experience.

“My own mentor group still connects on WhatsApp every single week, years later. Having that sustained peer support was life-changing, and I want to help foster that same deep sense of community and connection for the incoming Fellows.”

“The Schmidt Science Fellows community transformed my trajectory.”