Dr. Kushol Gupta, a structural biologist at the University of Pennsylvania. In just five years, he’s become the world’s leading expert on molecular structures known as scaffolds that shape and organize human DNA. His laboratory studies the structure and function of nucleosomes—the fundamental, ~150-base pair units that package up to six linear feet of genetic material into each cell. Gupta and his team relied on emerging high-pressure small-angle X-ray scattering (HP-SAXS) techniques at the Cornell High Energy Synchrotron Source (CHESS). Their research revealed important differences between regular nucleosomes and CENP-A nucleosomes.
It was the researchers’ first groundbreaking study at CHESS’s beamline ID7A1. This facility is famous for its high-tech proficiency in high-pressure X-ray scattering experiments on biological samples. To do this, the researchers created a custom-built hydrostatic pressure cell. This powerful piece of equipment is capable of creating pressures upwards of 400 megapascals (MPa), or roughly 4,000 times the pressure of the atmosphere. Gupta’s team applied massive amounts of pressure, making it possible to see how nucleosomes are structured and behave in these types of conditions.
The Role of Nucleosomes in DNA Packaging
Nucleosomes serve as the fundamental structural units of chromatin. They package and condense DNA within the nucleus of eukaryotic cells. Each nucleosome contains DNA wrapped around an octamer of histone proteins, enabling rapid and compact storage of genetic information. This complex packaging is key for many cellular processes, including gene expression and DNA replication.
In this latest study, Gupta’s team targeted how different types of nucleosomes reacted to pressure. By gradually increasing the pressure on nucleosome samples in solution—up to 300 megapascals—the researchers observed significant changes in their structural configurations. What they found is that when pressure is applied, DNA unwraps from the histone core. This new discovery opens the door for powerful new insights into nucleosomal dynamics.
The results showed a dramatic contrast between traditional nucleosomes and the specialized CENP-A nucleosomes. These two types are particularly notable because of their unique makeup and purposes. CENP-A nucleosomes are critical to preserving centromere identity and function over cell division cycles. By teasing apart their structure, we have the potential to learn extremely valuable information about genomic stability and inheritance.
Innovative Techniques at CHESS
Here, conditions of high pressure, together with small-angle scattering, open a new frontier in structural biology. This has proven to be particularly powerful for the study of biological samples. CHESS beamline ID7A1 is one of the very few facilities in the US. There, researchers can conduct high-pressure X-ray scattering experiments. This high-pressure/high-temperature experimental capability opens new avenues of exploration for molecular behaviors that are otherwise difficult to study under typical lab conditions.
Dr. Gupta’s innovative research not only enhances our understanding of nucleosome structures, but illustrates the wide-ranging applicability and power of HP-SAXS techniques. He is not just talking about these approaches, he’s using them on the projects of his day job. His research involves studies of vaccine candidate particles, protein-protein interactions, enzyme-ligand binding states. Such investigations would represent a major breakthrough in biomedical research and therapeutic development.
Gupta and his team are doing exciting, cutting-edge work at CHESS. Doing so will allow them to investigate how their findings impact our understanding of cellular processes or disease mechanisms. The lessons learned through high-pressure studies have the power to completely transform our knowledge in areas like genetics and molecular biology.
Implications and Future Directions
Gupta’s study has been released in advance online edition of Chromosome Research. Indeed this important work, DOI 10.1007/s10577-025-09769-z, helps to solidify the importance of the structural biology field within those discussions. This research does more than just shed light on nucleosome structures. It really could revolutionize how scientists approach the regulation of genetics and even the hefty study of chromosomal behavior.
Figuring out how nucleosomes react to mechanical stress obligate exceptional understanding. This understanding can further pave the way to understand how cells preserve DNA integrity across various physiological states. That’s why Gupta is excited to psyching up for new applications of HP-SAXS techniques. Future studies will continue to uncover transformative insights into these, and other, complex biological systems.