Metal Binding to Nsp1, a SARS-CoV-2 protein

Citation

Morales, Maryann (2025) Metal Binding to Nsp1, a SARS-CoV-2 protein. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/z9m9-yn02. https://resolver.caltech.edu/CaltechTHESIS:05302025-004839918

Abstract

The COVID-19 pandemic, caused by SARS-CoV-2, has underscored the need for novel antiviral strategies beyond vaccines. A key virulence factor in SARS-CoV-2 is nonstructural protein 1 (Nsp1), which suppresses host immune responses by degrading mRNA, inhibiting nuclear export, and binding to the 40S ribosomal subunit to block host translation. Its intrinsically disordered C-terminal domain complicates structure-based drug design, prompting exploration of alternative approaches.

This work investigates the use of transition metal coordination to target disordered regions of Nsp1. Copper(II) and cobalt(III) complexes were examined for their ability to bind histidine residues—particularly H165, critical for ribosome interaction. Biophysical techniques, including fluorescence spectroscopy, EPR, and ⁵⁹Co NMR, along with computational modeling, were used to characterize binding to Nsp1-derived peptides and the full-length protein.

Cu(II) displayed pH-dependent coordination through histidine and backbone amides, while oxidized Co(III) complexes formed stable, substitution-inert interactions. Multi-site binding and distinct kinetic profiles were observed. In vitro translation assays showed that metal complexes can affect translation, though selective inhibition of Nsp1 remains challenging.Overall, this work provides a foundation for targeting disordered viral proteins using coordination chemistry.

Thesis Files