Document Type
Article
Publication Date
3-2023
Department
Department of Physics
Abstract
Evaluating protein structures in living cells remains a challenge. Here, we investigate Interleukin-4 receptor alpha (IL-4Rα) into which the non-canonical amino acid bicyclo[6.1.0]nonyne-lysine (BCNK) is incorporated by genetic code expansion. Bioorthogonal click labeling is performed with tetrazine-conjugated dyes. To quantify the reaction yield in situ, we develop brightness-calibrated ratiometric imaging, a protocol where fluorescent signals in confocal multi-color images are ascribed to local concentrations. Screening receptor mutants bearing BCNK in the extracellular domain uncovered site-specific variations of both click efficiency and Interleukin-4 binding affinity, indicating subtle well-defined structural perturbations. Molecular dynamics and continuum electrostatics calculations suggest solvent polarization to determine site-specific variations of BCNK reactivity. Strikingly, signatures of differential click efficiency, measured for IL-4Rα in ligand-bound and free form, mirror sub-angstrom deformations of the protein backbone at corresponding locations. Thus, click efficiency by itself represents a remarkably informative readout linked to protein structure and dynamics in the native plasma membrane.
Publication Title
Nature Communications
Recommended Citation
Steiert, F.,
Schultz, P.,
Höfinger, S.,
Müller, T.,
Schwille, P.,
&
Weidemann, T.
(2023).
Insights into receptor structure and dynamics at the surface of living cells.
Nature Communications,
14(1).
http://doi.org/10.1038/s41467-023-37284-4
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/16943
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Version
Publisher's PDF
Publisher's Statement
© The Author(s) 2023. Publisher’s version of record: https://doi.org/10.1038/s41467-023-37284-4