October 9, 2026 Researchers make ‘molecular movies’ with powerful X-rays to help advance therapeutics | Newswise

Modern ultrafast science has moved far beyond examining static biological structures. Researchers working with powerful X-ray free-electron lasers can now record what amounts to molecular cinema, observing complex chemical changes on timescales measured in millionths of a billionth of a second at room temperature without damaging samples. This experimental capability relies on the Linac Coherent Light Source, a Department of Energy Office of Science user facility operated by Stanford University. As the primary backer of basic physical science research nationwide, the Office of Science tackles several of the most critical challenges facing the United States today. Operating globally utilized investigative tools, the SLAC National Accelerator Laboratory investigates how the universe functions across massive, microscopic, and ultra-fast dimensions.

Studying AspH and IPNS Enzymes with Ultrafast X-Rays

Two distinct enzymes have become the focus of this advanced imaging work: AspH, which is implicated in aggressive cancers like glioblastoma, and isopenicillin N synthase, commonly known as IPNS. In human biology, the AspH enzyme is encoded by the AspH gene, and scientists have documented elevated levels of this protein across multiple tumor types. By mapping how the enzyme regulates its own structure and function, researchers see potential to use AspH as both a biomarker and a therapeutic target. A specific category of biological proteins known as 2-oxoglutarate-dependent oxygenases facilitates numerous chemical reactions affecting cellular genetic code usage and various synthesis processes.

Meanwhile, the IPNS enzyme handles a critical early-stage reaction during the microbial fermentation process required to make penicillin. Because natural penicillin possesses a remarkable structure made up of two reactive rings, as a consequence, it cannot be made by chemical synthesis. Instead, it is made by fermentation in microbial cells.

Capturing Intermediates at the Macromolecular Femtosecond Crystallography Instrument

Observing the intermediate molecules that form and vanish midway through an enzymatic reaction has historically tested the limits of experimental chemistry. Although scientific teams have investigated how these enzymes drive reactions for extended periods, isolating transient molecules—those generated and subsequently depleted mid-reaction—has proven difficult. To solve this, scientists at the Macromolecular Femtosecond Crystallography instrument prepare microcrystal samples of the target enzymes and pass them through a specialized system that injects oxygen to trigger the reaction. As ultrabright X-ray bursts scatter off the sample in real time, researchers record atomic details that reveal how the chemistry unfolds. Utilizing exceptionally intense and brief X-ray pulses, the team captures these biological samples at room temperature in atomic detail on a femtosecond timescale without causing structural damage.

“We have been working for many years to develop experimental protocols that allow us to precisely start the reaction in these fascinating enzymes and watch them perform complicated chemistry step by step in real time,”

Kern

The work is led by international teams including researchers from De Munnik et al., published in Nature Communications on 25 February 2026, and Rabe et al., published in Nature Catalysis on 09 October 2026. Additional medical research from Memorial Sloan Kettering Cancer Center features work led by Nancy Santiappillai, PhD, a postdoctoral researcher in the Keshari Lab, who used advanced spatial metabolomics to identify why drugs designed to block the primary fuel source of triple-negative breast cancer—the amino acid glutamine—have had limited success in the clinic.

Surprising Structural Mechanics Revealed in Penicillin Biosynthesis

While researchers knew that iron atoms played a central role in driving these enzymatic reactions, the atomic-level snapshots yielded unexpected mechanics. Observation revealed that an iron-coordinated water molecule stays intact throughout the entire reaction process, indicating a potentially vital role in enabling catalysis. Although the group recognized that iron-bound water was necessary for catalysis, observing this persistence—and demonstrating that interrupting it halts the reaction entirely—might aid investigators in formulating treatments targeting AspH behavior in cancerous cells. When analyzing IPNS during the assembly of penicillin rings, the team discovered surprising ways these enzymes catalyze reactions.

“We wanted to understand specifically how enzymes are controlling the intermediates,”

Rabe

The investigation also revealed that specific water molecules located within the active site actively steer the chemical outcome. According to the published findings, these insights into enzyme control could allow scientists to better understand the structure and function of these enzymes, potentially using them as biomarkers and therapeutic targets for cancer, or for a method to develop new antibiotics.