C-Mannosylation supports folding and enhances stability of thrombospondin repeats
- Hannover Medical School, Germany
- Universitat Autònoma de Barcelona, Spain
Abstract
Previous studies demonstrated importance of C-mannosylation for efficient protein secretion. To study its impact on protein folding and stability, we analyzed both C-mannosylated and non-C-mannosylated thrombospondin type 1 repeats (TSRs) of netrin receptor UNC-5. In absence of C-mannosylation, UNC-5 TSRs could only be obtained at low temperature and a significant proportion displayed incorrect intermolecular disulfide bridging, which was hardly observed when C-mannosylated. Glycosylated TSRs exhibited higher resistance to thermal and reductive denaturation processes and the presence of C-mannoses promoted the oxidative folding of a reduced and denatured TSR in vitro. Molecular dynamics simulations supported the experimental studies and showed that C-mannoses can be involved in intramolecular hydrogen bonding and limit the flexibility of the TSR tryptophan-arginine ladder. We propose that in the endoplasmic reticulum folding process, C-mannoses orient the underlying tryptophan residues and facilitate the formation of the tryptophan arginine ladder, thereby influencing the positioning of cysteines and disulfide bridging.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 3, 4 and 5
Article and author information
Author details
Aleksandra Shcherbakova
Funding
Deutsche Forschungsgemeinschaft (FOR2509 BA 4091/6-1)
- Hans Bakker
Deutsche Forschungsgemeinschaft (BA 4091/5-1)
- Hans Bakker
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Shcherbakova et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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C-Mannosylation supports folding and enhances stability of thrombospondin repeats
eLife 8:e52978.
https://doi.org/10.7554/eLife.52978
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