MCF Special Seminar

Conformational ensemble of USP7 as determined by hybrid SAXS-NMR structure: Combining low-resolution and high atomic-resolution methods

Dysregulation of USP7 is associated with neurodevelopmental disorders and various cancers, making it an attractive target for therapeutic intervention. USP7 (~130 kDa) contains multiple domains, including a catalytic domain (CD) and several ubiquitin-like domains, which interact with substrates and regulate enzyme activity. Interaction between C-terminus tail and Catalytic Domain (CD) of Ubiquitin Specific Protease 7 (USP7) in presence of substrate gives rise to an active conformation, considered to be crucial for the enzyme activity. Conversely, the C-terminal tail moves back to its original position (away from CD) leading to the L-shaped structure known as extended/inactive conformation of USP7. Till date 71 PDBs have been submitted for several USP7 fragments that have been structurally characterized at atomic resolution. Despite these insights, structural details of full-length USP7 (FL-USP7) remain elusive. Here, I present my progress in the structural and functional characterization of FL-USP7 using an integrated approach combining Nuclear Magnetic Resonance (NMR) Spectroscopy, Small-Angle X-ray Scattering (SAXS), and multi-state modeling (MultiFoXS). Our results reveal that FL-USP7 exists as a conformational ensemble in its apo form, with multiple co-existing conformations and significant inter-domain interactions. Conformational sampling reveals that Apo form of the USP7 protein consists of majority 80% as extended/inactive state with minor 20% of population as closed/active state. These findings provide new insights into USP7 activation and its functional dynamics, representing a significant step toward understanding its substrate specificity and catalytic mechanism.

Dr. Nancy Jaiswal

Dr. Nancy Jaiswal is an accomplished biophysicist specializing in the study of therapeutically relevant macromolecules and their potential applications in drug discovery, particularly in the context of public health. Her passion for integrating diverse scientific approaches to investigate complex biological systems drives her innovative research.

Dr. Jaiswal earned her Ph.D. in 2019 from the Center for Biomedical Research in India, where she focused on protein Nuclear Magnetic Resonance (NMR). During her doctoral research, she made notable contributions, including the NMR assignment of different populations of simultaneously existing protein states in solution, as well as conducting detailed conformational characterization and studying protein–DNA and protein–protein interactions.

In 2020, Dr. Jaiswal joined the University of Connecticut as a Postdoctoral Researcher, where she studied the highly dynamic USP7 enzyme. She expanded her expertise by combining NMR with Small Angle X-ray Scattering (SAXS) to generate the overall structural envelope of this enzyme, whose full-length structure had remained elusive. Through this work, she demonstrated the power of integrating multiple biophysical techniques to obtain more comprehensive insights into protein structures.

Building on her experiences, Dr. Jaiswal joined Indiana University as an Assistant Research Professor in 2023. At Indiana, she continues to apply a broad range of biophysical methods, including Surface Plasmon Resonance (SPR) and Cryo-Electron Microscopy (Cryo-EM), to further advance her research on protein structure and function.

To date, Dr. Jaiswal has authored 13 publications, with 3 submissions to the Biological Magnetic Resonance Bank (BMRB) and 3 submissions to the Protein Data Bank (PDB). Her ongoing work continues to bridge the gap between structural biology and therapeutic development.