Regulatory nascent chains interact with the ribosomal exit tunnel and modulate their own translation. To characterize nascent chain recognition by the ribosome at the atomic level, extensive molecular dynamics simulations of TnaC, the leader peptide of the tryptophanase operon, inside the exit tunnel were performed for an aggregate time of 2.1 mus. The simulations, complemented by quantum chemistry calculations, suggest that the critical TnaC residue W12 is recognized by the ribosome via a cation-pi interaction, whereas TnaC's D16 forms salt bridges with ribosomal proteins. The simulations also show that TnaC-mediated translational arrest does not involve a swinging of ribosomal protein L22, as previously proposed. Furthermore, bioinformatic analyses and simulations suggest nascent chain elements that may prevent translational arrest in various organisms. Altogether, the current study unveils atomic-detail interactions that explain the role of elements of TnaC and the ribosome essential for translational arrest.
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http://dx.doi.org/10.1016/j.str.2010.02.011 | DOI Listing |
Rev Physiol Biochem Pharmacol
January 2025
Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK.
Ribosomes use multiple electrical forces to regulate new protein construction, to ensure efficient protein cotranslation, chaperoning, and folding. When these electrical regulatory forces are disrupted as in point charge mutations, specific disease occurs from aberrantly folded proteins. α1 antitrypsin deficiency is perhaps the best-known misfolded protein disease and is covered in some detail.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Biochemistry, University of Zurich, Winterthurerstrass 190, 8057 Zurich, Switzerland.
Type III clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) systems (type III CRISPR-Cas systems) use guide RNAs to recognize RNA transcripts of foreign genetic elements, which triggers the generation of cyclic oligoadenylate (cOA) second messengers by the Cas10 subunit of the type III effector complex. In turn, cOAs bind and activate ancillary effector proteins to reinforce the host immune response. Type III systems utilize distinct cOAs, including cyclic tri- (cA3), tetra- (cA4) and hexa-adenylates (cA6).
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Sinopec Key Laboratory of Research and Application of Medical and Hygienic Materials, SINOPEC (Beijing) Research Institute of Chemical Industry Co., Ltd., No. 14 Beisanhuan Donglu, Chao Yang District, Beijing 100013, China.
Disentangled ultra-high-molecular-weight polyethylene (-UHMWPE) solves the problem of the difficult processing of traditional UHMWPE caused by entanglements between molecular chains. In this review, we look into the innovative realm of nascent disentangled UHMWPE, concentrating on the recent advances achieved through the in situ polymerization of ethylene by single-site catalysts. The effect of single-site catalysts and polymerization conditions on the molecular characteristics is discussed in detail from the perspective of mechanism and DFT calculations.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Cell & Molecular Biology, Uppsala University, Uppsala SE-75124, Sweden.
The bacterial chaperone Trigger factor (TF) binds to ribosome-nascent chain complexes (RNCs) and cotranslationally aids the folding of proteins in bacteria. Decades of studies have given a broad, but often conflicting, description of the substrate specificity of TF, its RNC-binding dynamics, and competition with other RNC-binding factors, such as the Signal Recognition Particle (SRP). Previous RNC-binding kinetics experiments were commonly conducted on stalled RNCs in reconstituted systems, and consequently, may not be representative of the interaction of TF with ribosomes translating mRNA in the cytoplasm of the cell.
View Article and Find Full Text PDFJ Transl Med
December 2024
Cancer Institute, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
Background: Increased ribosome biogenesis is required for tumor growth. In this study, we investigated the function and underlying molecular mechanism of ribosome biogenesis factor (RBIS) in the progression of non-small cell lung cancer (NSCLC).
Methods: In our study, we conducted a comprehensive analysis to identify key genes implicated in ribosome biogenesis by leveraging a Gene Set Enrichment Analysis (GSEA) dataset.
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