Protein-Cadmium Interactions in Crowded Biomolecular Environments Probed by In-celland Lysate NMR Spectroscopy

Katti, S. S.; Igumenova, T. I.

doi:10.1101/2023.11.03.565546

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bioRxiv · 10.1101/2023.11.03.565546

Protein-Cadmium Interactions in Crowded Biomolecular Environments Probed by In-celland Lysate NMR Spectroscopy

Katti, S. S.·Igumenova, T. I.

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Abstract

One of the mechanisms by which toxic metal ions interfere with cellular functions is ionic mimicry, where they bind to protein sites in lieu of native metals Ca2+ and Zn2+. The influence of crowded intracellular environments on these interactions is not well understood. Here, we demonstrate the application of in-cell and lysate NMR spectroscopy to obtain atomic-level information on how a potent environmental toxin cadmium interacts with its protein targets. The experiments, conducted in intact E. coli cells and their lysates, revealed that Cd2+ can profoundly affect the quinary interactions of its protein partners, and can replace Zn2+ in both labile and non-labile protein structural sites without significant perturbation of the membrane binding function. Surprisingly, in crowded molecular environments Cd2+ can effectively target not only all-sulfur and mixed sulfur/nitrogen but also all-oxygen coordination sites. The sulfur-rich coordination environments show significant promise for bioremedial applications, as demonstrated by the ability of the designed protein scaffold 3DIV to sequester intracellular cadmium. Our data suggests that in-cell NMR spectroscopy is a powerful tool for probing interactions of toxic metal ions with their potential protein targets, and for the assessment of potency of sequestering agents.

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Katti, S. S., Igumenova, T. I.. 2023-11-05. Protein-Cadmium Interactions in Crowded Biomolecular Environments Probed by In-celland Lysate NMR Spectroscopy. https://doi.org/10.1101/2023.11.03.565546

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