How do the key features of protein folding, elucidated from studies on native, isolated proteins, manifest in cotranslational folding on the ribosome? Using a well-characterized family of homologous α-helical proteins with a range of biophysical properties, we show that spectrin domains can fold vectorially on the ribosome and may do so via a pathway different from that of the isolated domain. We use cryo-EM to reveal a folded or partially folded structure, formed in the vestibule of the ribosome. Our results reveal that it is not possible to predict which domains will fold within the ribosome on the basis of the folding behavior of isolated domains; instead, we propose that a complex balance of the rate of folding, the rate of translation and the lifetime of folded or partly folded states will determine whether folding occurs cotranslationally on actively translating ribosomes.
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http://dx.doi.org/10.1038/nsmb.3355 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Computer Science, University of Haifa, Haifa 3303221, Israel.
Selective pressure acts on the codon use, optimizing multiple, overlapping signals that are only partially understood. We trained AI models to predict codons given their amino acid sequence in the eukaryotes and and the bacteria and to study the extent to which we can learn patterns in naturally occurring codons to improve predictions. We trained our models on a subset of the proteins and evaluated their predictions on large, separate sets of proteins of varying lengths and expression levels.
View Article and Find Full Text PDFPLoS Comput Biol
December 2024
Department of Biomedical Engineering, the Engineering Faculty, Tel Aviv University, Tel-Aviv, Israel.
The P-glycoprotein efflux pump, encoded by the MDR1 gene, is an ATP-driven transporter capable of expelling a diverse array of compounds from cells. Overexpression of this protein is implicated in the multi-drug resistant phenotype observed in various cancers. Numerous studies have attempted to decipher the impact of genetic variants within MDR1 on P-glycoprotein expression, functional activity, and clinical outcomes in cancer patients.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
Nat Commun
November 2024
Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel.
The proper folding of multispanning membrane proteins (MPs) hinges on the accurate insertion of their transmembrane helices (TMs) into the membrane. Predominantly, TMs are inserted during protein translation, via a conserved mechanism centered around the Sec translocon. Our study reveals that the C-terminal TMs (cTMs) of numerous MPs across various organisms bypass this cotranslational route, necessitating an alternative posttranslational insertion strategy.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Department of Biosciences and Informatics, Keio University, Yokohama, Japan. Electronic address:
The translational arrest is a phenomenon wherein a temporary pause or slowing of the translation elongation reaction occurs due to the interaction between ribosome and nascent peptide. Recent studies have revealed that translational arrest peptides are involved in intracellular protein homeostasis regulatory functions, such as gene expression regulation at the translational level and regulation of cotranslational protein folding. Herein, we established a method for the large-scale in vitro selection of translational arrest peptides from DNA libraries by combining a modified mRNA display method and deep sequencing.
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