1. Nascent chains derived from a foldable protein sequence interact with specific ribosomal surface sites near the exit tunnel.
- Author
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Masse MM, Guzman-Luna V, Varela AE, Mahfuza Shapla U, Hutchinson RB, Srivastava A, Wei W, Fuchs AM, and Cavagnero S
- Subjects
- Protein Binding, Molecular Chaperones metabolism, Molecular Chaperones chemistry, Intrinsically Disordered Proteins metabolism, Intrinsically Disordered Proteins chemistry, Protein Biosynthesis, Models, Molecular, Protein Conformation, Humans, Ribosomes metabolism, Ribosomal Proteins metabolism, Ribosomal Proteins chemistry, Protein Folding
- Abstract
In order to become bioactive, proteins must be translated and protected from aggregation during biosynthesis. The ribosome and molecular chaperones play a key role in this process. Ribosome-bound nascent chains (RNCs) of intrinsically disordered proteins and RNCs bearing a signal/arrest sequence are known to interact with ribosomal proteins. However, in the case of RNCs bearing foldable protein sequences, not much information is available on these interactions. Here, via a combination of chemical crosslinking and time-resolved fluorescence-anisotropy, we find that nascent chains of the foldable globin apoHmp
1-140 interact with ribosomal protein L23 and have a freely-tumbling non-interacting N-terminal compact region comprising 63-94 residues. Longer RNCs (apoHmp1-189 ) also interact with an additional yet unidentified ribosomal protein, as well as with chaperones. Surprisingly, the apparent strength of RNC/r-protein interactions does not depend on nascent-chain sequence. Overall, foldable nascent chains establish and expand interactions with selected ribosomal proteins and chaperones, as they get longer. These data are significant because they reveal the interplay between independent conformational sampling and nascent-protein interactions with the ribosomal surface., (© 2024. The Author(s).)- Published
- 2024
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