Understanding the conformational sampling of translation-arrested ribosome nascent chain complexes is key to understand co-translational folding. Up to now, coupling of cysteine oxidation, disulfide bond formation and structure formation in nascent chains has remained elusive. Here, we investigate the eye-lens protein γB-crystallin in the ribosomal exit tunnel. Using mass spectrometry, theoretical simulations, dynamic nuclear polarization-enhanced solid-state nuclear magnetic resonance and cryo-electron microscopy, we show that thiol groups of cysteine residues undergo S-glutathionylation and S-nitrosylation and form non-native disulfide bonds. Thus, covalent modification chemistry occurs already prior to nascent chain release as the ribosome exit tunnel provides sufficient space even for disulfide bond formation which can guide protein folding.
We acknowledge help from Anja Seybert, Margot Frangakis, Diana Grewe, Mikhail Eltsov, Utz Ermel, and Shintaro Aibara. The work was supported by Deutsche Forschungsgemeinschaft in the CLiC graduate school. Work at the Center for Biomolecular Magnetic Resonance (BMRZ) is supported by the German state of Hesse. The work at BMRZ has been supported by the state of Hesse. L.S. has been supported by the DFG graduate college: CLiC.
Schulte L, Mao J, Reitz J, et al. Cysteine oxidation and disulfide formation in the ribosomal exit tunnel. Nature Communications. 2020;11. doi:10.1038/s41467-020-19372-x
Schulte, L., Mao, J., Reitz, J., Sreeramulu, S., Kudlinzki, D., Hodirnau, V.-V., … Schwalbe, H. (2020). Cysteine oxidation and disulfide formation in the ribosomal exit tunnel. Nature Communications, 11. https://doi.org/10.1038/s41467-020-19372-x
Schulte, Linda, Jiafei Mao, Julian Reitz, Sridhar Sreeramulu, Denis Kudlinzki, Victor-Valentin Hodirnau, Jakob Meier-Credo, et al. “Cysteine Oxidation and Disulfide Formation in the Ribosomal Exit Tunnel.” Nature Communications 11 (2020). https://doi.org/10.1038/s41467-020-19372-x.
L. Schulte et al., “Cysteine oxidation and disulfide formation in the ribosomal exit tunnel,” Nature Communications, vol. 11, 2020.
Schulte L, Mao J, Reitz J, Sreeramulu S, Kudlinzki D, Hodirnau V-V, Meier-Credo J, Saxena K, Buhr F, Langer JD, Blackledge M, Frangakis AS, Glaubitz C, Schwalbe H. 2020. Cysteine oxidation and disulfide formation in the ribosomal exit tunnel. Nature Communications. 11.
Schulte, Linda, et al. “Cysteine Oxidation and Disulfide Formation in the Ribosomal Exit Tunnel.” Nature Communications, vol. 11, 5569, Springer Nature, 2020, doi:10.1038/s41467-020-19372-x.
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