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Vu QV, Nissley DA, Jiang Y, O'Brien EP, Li MS. Is Posttranslational Folding More Efficient Than Refolding from a Denatured State: A Computational Study. J Phys Chem B 2023. [PMID: 37200608 DOI: 10.1021/acs.jpcb.3c01694] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The folding of proteins into their native conformation is a complex process that has been extensively studied over the past half-century. The ribosome, the molecular machine responsible for protein synthesis, is known to interact with nascent proteins, adding further complexity to the protein folding landscape. Consequently, it is unclear whether the folding pathways of proteins are conserved on and off the ribosome. The main question remains: to what extent does the ribosome help proteins fold? To address this question, we used coarse-grained molecular dynamics simulations to compare the mechanisms by which the proteins dihydrofolate reductase, type III chloramphenicol acetyltransferase, and d-alanine-d-alanine ligase B fold during and after vectorial synthesis on the ribosome to folding from the full-length unfolded state in bulk solution. Our results reveal that the influence of the ribosome on protein folding mechanisms varies depending on the size and complexity of the protein. Specifically, for a small protein with a simple fold, the ribosome facilitates efficient folding by helping the nascent protein avoid misfolded conformations. However, for larger and more complex proteins, the ribosome does not promote folding and may contribute to the formation of intermediate misfolded states cotranslationally. These misfolded states persist posttranslationally and do not convert to the native state during the 6 μs runtime of our coarse-grain simulations. Overall, our study highlights the complex interplay between the ribosome and protein folding and provides insight into the mechanisms of protein folding on and off the ribosome.
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Affiliation(s)
- Quyen V Vu
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Daniel A Nissley
- Department of Statistics, University of Oxford, Oxford OX1 3LB, U.K
| | - Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Edward P O'Brien
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Institute for Computational and Data Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mai Suan Li
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
- Institute for Computational Sciences and Technology, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
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2
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Jiang Y, Neti SS, Sitarik I, Pradhan P, To P, Xia Y, Fried SD, Booker SJ, O'Brien EP. How synonymous mutations alter enzyme structure and function over long timescales. Nat Chem 2023; 15:308-318. [PMID: 36471044 PMCID: PMC11267483 DOI: 10.1038/s41557-022-01091-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 10/17/2022] [Indexed: 12/12/2022]
Abstract
The specific activity of enzymes can be altered over long timescales in cells by synonymous mutations that alter a messenger RNA molecule's sequence but not the encoded protein's primary structure. How this happens at the molecular level is unknown. Here, we use multiscale modelling of three Escherichia coli enzymes (type III chloramphenicol acetyltransferase, D-alanine-D-alanine ligase B and dihydrofolate reductase) to understand experimentally measured changes in specific activity due to synonymous mutations. The modelling involves coarse-grained simulations of protein synthesis and post-translational behaviour, all-atom simulations to test robustness and quantum mechanics/molecular mechanics calculations to characterize enzymatic function. We show that changes in codon translation rates induced by synonymous mutations cause shifts in co-translational and post-translational folding pathways that kinetically partition molecules into subpopulations that very slowly interconvert to the native, functional state. Structurally, these states resemble the native state, with localized misfolding near the active sites of the enzymes. These long-lived states exhibit reduced catalytic activity, as shown by their increased activation energies for the reactions they catalyse.
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Affiliation(s)
- Yang Jiang
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA
| | - Syam Sundar Neti
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA
| | - Ian Sitarik
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA
| | - Priya Pradhan
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA
| | - Philip To
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
| | - Yingzi Xia
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
| | - Stephen D Fried
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, USA
- Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Squire J Booker
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
- Howard Hughes Medical Institute, Pennsylvania State University, University Park, PA, USA
| | - Edward P O'Brien
- Department of Chemistry, Pennsylvania State University, University Park, PA, USA.
- Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA.
- Institute for Computational and Data Sciences, Pennsylvania State University, University Park, PA, USA.
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3
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Nissley DA, Jiang Y, Trovato F, Sitarik I, Narayan KB, To P, Xia Y, Fried SD, O’Brien EP. Universal protein misfolding intermediates can bypass the proteostasis network and remain soluble and less functional. Nat Commun 2022; 13:3081. [PMID: 35654797 PMCID: PMC9163053 DOI: 10.1038/s41467-022-30548-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 05/05/2022] [Indexed: 01/12/2023] Open
Abstract
Some misfolded protein conformations can bypass proteostasis machinery and remain soluble in vivo. This is an unexpected observation, as cellular quality control mechanisms should remove misfolded proteins. Three questions, then, are: how do long-lived, soluble, misfolded proteins bypass proteostasis? How widespread are such misfolded states? And how long do they persist? We address these questions using coarse-grain molecular dynamics simulations of the synthesis, termination, and post-translational dynamics of a representative set of cytosolic E. coli proteins. We predict that half of proteins exhibit misfolded subpopulations that bypass molecular chaperones, avoid aggregation, and will not be rapidly degraded, with some misfolded states persisting for months or longer. The surface properties of these misfolded states are native-like, suggesting they will remain soluble, while self-entanglements make them long-lived kinetic traps. In terms of function, we predict that one-third of proteins can misfold into soluble less-functional states. For the heavily entangled protein glycerol-3-phosphate dehydrogenase, limited-proteolysis mass spectrometry experiments interrogating misfolded conformations of the protein are consistent with the structural changes predicted by our simulations. These results therefore provide an explanation for how proteins can misfold into soluble conformations with reduced functionality that can bypass proteostasis, and indicate, unexpectedly, this may be a wide-spread phenomenon.
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Affiliation(s)
- Daniel A. Nissley
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA
| | - Yang Jiang
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA
| | - Fabio Trovato
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA
| | - Ian Sitarik
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA
| | - Karthik B. Narayan
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA
| | - Philip To
- grid.21107.350000 0001 2171 9311Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Yingzi Xia
- grid.21107.350000 0001 2171 9311Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Stephen D. Fried
- grid.21107.350000 0001 2171 9311Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218 USA ,grid.21107.350000 0001 2171 9311Thomas C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Edward P. O’Brien
- grid.29857.310000 0001 2097 4281Department of Chemistry, Pennsylvania State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Bioinformatics and Genomics Graduate Program, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Institute for Computational and Data Sciences, Pennsylvania State University, University Park, PA 16802 USA
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4
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Shishido H, Yoon JS, Skach WR. A small molecule high throughput screening platform to profile conformational properties of nascent, ribosome-bound proteins. Sci Rep 2022; 12:2509. [PMID: 35169219 PMCID: PMC8847357 DOI: 10.1038/s41598-022-06456-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 01/18/2022] [Indexed: 12/16/2022] Open
Abstract
Genetic mutations cause a wide spectrum of human disease by disrupting protein folding, both during and after synthesis. Transient de-novo folding intermediates therefore represent potential drug targets for pharmacological correction of protein folding disorders. Here we develop a FRET-based high-throughput screening (HTS) assay in 1,536-well format capable of identifying small molecules that interact with nascent polypeptides and correct genetic, cotranslational folding defects. Ribosome nascent chain complexes (RNCs) containing donor and acceptor fluorophores were isolated from cell free translation reactions, immobilized on Nickel-NTA/IDA beads, and imaged by high-content microscopy. Quantitative FRET measurements obtained from as little as 0.4 attomole of protein/bead enabled rapid assessment of conformational changes with a high degree of reproducibility. Using this assay, we performed a pilot screen of ~ 50,000 small molecules to identify compounds that interact with RNCs containing the first nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) harboring a disease-causing mutation (A455E). Screen results yielded 133 primary hits and 1 validated hit that normalized FRET values of the mutant nascent peptide. This system provides a scalable, tractable, structure-based discovery platform for screening small molecules that bind to or impact the folding of protein substrates that are not amenable to traditional biochemical analyses.
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Affiliation(s)
- Hideki Shishido
- CFFT Lab, Cystic Fibrosis Foundation, 44 Hartwell Ave, Lexington, MA, 02421, USA.,Generate Biomedicines, Inc., 26 Landsdowne St, Cambridge, MA, 02139, USA
| | - Jae Seok Yoon
- CFFT Lab, Cystic Fibrosis Foundation, 44 Hartwell Ave, Lexington, MA, 02421, USA
| | - William R Skach
- Cystic Fibrosis Foundation, 4550 Montgomery Ave., Suite 1100N, Bethesda, MD, 20814, USA.
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5
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Abstract
Summary Motivation. Predicting the native state of a protein has long been considered a gateway problem for understanding protein folding. Recent advances in structural modeling driven by deep learning have achieved unprecedented success at predicting a protein’s crystal structure, but it is not clear if these models are learning the physics of how proteins dynamically fold into their equilibrium structure or are just accurate knowledge-based predictors of the final state. Results. In this work, we compare the pathways generated by state-of-the-art protein structure prediction methods to experimental data about protein folding pathways. The methods considered were AlphaFold 2, RoseTTAFold, trRosetta, RaptorX, DMPfold, EVfold, SAINT2 and Rosetta. We find evidence that their simulated dynamics capture some information about the folding pathway, but their predictive ability is worse than a trivial classifier using sequence-agnostic features like chain length. The folding trajectories produced are also uncorrelated with experimental observables such as intermediate structures and the folding rate constant. These results suggest that recent advances in structure prediction do not yet provide an enhanced understanding of protein folding. Availability. The data underlying this article are available in GitHub at https://github.com/oxpig/structure-vs-folding/ Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Carlos Outeiral
- Department of Statistics, University of Oxford, Oxford OX1 3PB, UK
| | - Daniel A Nissley
- Department of Statistics, University of Oxford, Oxford OX1 3PB, UK
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6
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Koubek J, Schmitt J, Galmozzi CV, Kramer G. Mechanisms of Cotranslational Protein Maturation in Bacteria. Front Mol Biosci 2021; 8:689755. [PMID: 34113653 PMCID: PMC8185961 DOI: 10.3389/fmolb.2021.689755] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/10/2021] [Indexed: 01/05/2023] Open
Abstract
Growing cells invest a significant part of their biosynthetic capacity into the production of proteins. To become functional, newly-synthesized proteins must be N-terminally processed, folded and often translocated to other cellular compartments. A general strategy is to integrate these protein maturation processes with translation, by cotranslationally engaging processing enzymes, chaperones and targeting factors with the nascent polypeptide. Precise coordination of all factors involved is critical for the efficiency and accuracy of protein synthesis and cellular homeostasis. This review provides an overview of the current knowledge on cotranslational protein maturation, with a focus on the production of cytosolic proteins in bacteria. We describe the role of the ribosome and the chaperone network in protein folding and how the dynamic interplay of all cotranslationally acting factors guides the sequence of cotranslational events. Finally, we discuss recent data demonstrating the coupling of protein synthesis with the assembly of protein complexes and end with a brief discussion of outstanding questions and emerging concepts in the field of cotranslational protein maturation.
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Affiliation(s)
- Jiří Koubek
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jaro Schmitt
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Carla Veronica Galmozzi
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Günter Kramer
- Center for Molecular Biology of Heidelberg University (ZMBH) and German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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7
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Urrutia J, Aguado A, Gomis-Perez C, Muguruza-Montero A, Ballesteros OR, Zhang J, Nuñez E, Malo C, Chung HJ, Leonardo A, Bergara A, Villarroel A. An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel. BMC Biol 2021; 19:109. [PMID: 34020651 PMCID: PMC8138981 DOI: 10.1186/s12915-021-01040-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 04/29/2021] [Indexed: 12/21/2022] Open
Abstract
Background The amino acid sequence of proteins generally carries all the necessary information for acquisition of native conformations, but the vectorial nature of translation can additionally determine the folding outcome. Such consideration is particularly relevant in human diseases associated to inherited mutations leading to structural instability, aggregation, and degradation. Mutations in the KCNQ2 gene associated with human epilepsy have been suggested to cause misfolding of the encoded Kv7.2 channel. Although the effect on folding of mutations in some domains has been studied, little is known of the way pathogenic variants located in the calcium responsive domain (CRD) affect folding. Here, we explore how a Kv7.2 mutation (W344R) located in helix A of the CRD and associated with hereditary epilepsy interferes with channel function. Results We report that the epilepsy W344R mutation within the IQ motif of CRD decreases channel function, but contrary to other mutations at this site, it does not impair the interaction with Calmodulin (CaM) in vitro, as monitored by multiple in vitro binding assays. We find negligible impact of the mutation on the structure of the complex by molecular dynamic computations. In silico studies revealed two orientations of the side chain, which are differentially populated by WT and W344R variants. Binding to CaM is impaired when the mutated protein is produced in cellulo but not in vitro, suggesting that this mutation impedes proper folding during translation within the cell by forcing the nascent chain to follow a folding route that leads to a non-native configuration, and thereby generating non-functional ion channels that fail to traffic to proper neuronal compartments. Conclusions Our data suggest that the key pathogenic mechanism of Kv7.2 W344R mutation involves the failure to adopt a configuration that can be recognized by CaM in vivo but not in vitro. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01040-1.
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Affiliation(s)
- Janire Urrutia
- Instituto Biofisika, CSIC-UPV/EHU, 48940, Leioa, Spain.,Present address: Department of Physiology, Faculty of Medicine and Nursery, UPV/EHU, 48940, Leioa, Spain
| | | | - Carolina Gomis-Perez
- Instituto Biofisika, CSIC-UPV/EHU, 48940, Leioa, Spain.,Present address: Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | | | | | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Eider Nuñez
- Instituto Biofisika, CSIC-UPV/EHU, 48940, Leioa, Spain
| | | | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Aritz Leonardo
- Departamento de Física Aplicada II, Universidad del País Vasco, UPV/EHU, 48940, Leioa, Spain.,Donostia International Physics Center, 20018, Donostia, Spain
| | - Aitor Bergara
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, 20018, Donostia, Spain.,Donostia International Physics Center, 20018, Donostia, Spain.,Departmento de Materia Condensada, Universidad del País Vasco, UPV/EHU, 48940, Leioa, Spain
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8
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Liutkute M, Maiti M, Samatova E, Enderlein J, Rodnina MV. Gradual compaction of the nascent peptide during cotranslational folding on the ribosome. eLife 2020; 9:60895. [PMID: 33112737 PMCID: PMC7593090 DOI: 10.7554/elife.60895] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 10/16/2020] [Indexed: 12/21/2022] Open
Abstract
Nascent polypeptides begin to fold in the constrained space of the ribosomal peptide exit tunnel. Here we use force-profile analysis (FPA) and photo-induced energy-transfer fluorescence correlation spectroscopy (PET-FCS) to show how a small α-helical domain, the N-terminal domain of HemK, folds cotranslationally. Compaction starts vectorially as soon as the first α-helical segments are synthesized. As nascent chain grows, emerging helical segments dock onto each other and continue to rearrange at the vicinity of the ribosome. Inside or in the proximity of the ribosome, the nascent peptide undergoes structural fluctuations on the µs time scale. The fluctuations slow down as the domain moves away from the ribosome. Mutations that destabilize the packing of the domain's hydrophobic core have little effect on folding within the exit tunnel, but abolish the final domain stabilization. The results show the power of FPA and PET-FCS in solving the trajectory of cotranslational protein folding and in characterizing the dynamic properties of folding intermediates.
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Affiliation(s)
- Marija Liutkute
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Manisankar Maiti
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ekaterina Samatova
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Jörg Enderlein
- III. Institute of Physics - Biophysics, Georg August University, Göttingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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9
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Shishido H, Yoon JS, Yang Z, Skach WR. CFTR trafficking mutations disrupt cotranslational protein folding by targeting biosynthetic intermediates. Nat Commun 2020; 11:4258. [PMID: 32848127 PMCID: PMC7450043 DOI: 10.1038/s41467-020-18101-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 08/04/2020] [Indexed: 02/03/2023] Open
Abstract
Protein misfolding causes a wide spectrum of human disease, and therapies that target misfolding are transforming the clinical care of cystic fibrosis. Despite this success, however, very little is known about how disease-causing mutations affect the de novo folding landscape. Here we show that inherited, disease-causing mutations located within the first nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR) have distinct effects on nascent polypeptides. Two of these mutations (A455E and L558S) delay compaction of the nascent NBD1 during a critical window of synthesis. The observed folding defect is highly dependent on nascent chain length as well as its attachment to the ribosome. Moreover, restoration of the NBD1 cotranslational folding defect by second site suppressor mutations also partially restores folding of full-length CFTR. These findings demonstrate that nascent folding intermediates can play an important role in disease pathogenesis and thus provide potential targets for pharmacological correction.
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Affiliation(s)
- Hideki Shishido
- CFFT Lab, Cystic Fibrosis Foundation, 44 Hartwell Ave, Lexington, MA, 02421, USA
| | - Jae Seok Yoon
- CFFT Lab, Cystic Fibrosis Foundation, 44 Hartwell Ave, Lexington, MA, 02421, USA
| | - Zhongying Yang
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - William R Skach
- Cystic Fibrosis Foundation, 4550 Montgomery Ave., Suite 1100N, Bethesda, MD, 20814, USA.
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10
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Bowman JC, Petrov AS, Frenkel-Pinter M, Penev PI, Williams LD. Root of the Tree: The Significance, Evolution, and Origins of the Ribosome. Chem Rev 2020; 120:4848-4878. [PMID: 32374986 DOI: 10.1021/acs.chemrev.9b00742] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ribosome is an ancient molecular fossil that provides a telescope to the origins of life. Made from RNA and protein, the ribosome translates mRNA to coded protein in all living systems. Universality, economy, centrality and antiquity are ingrained in translation. The translation machinery dominates the set of genes that are shared as orthologues across the tree of life. The lineage of the translation system defines the universal tree of life. The function of a ribosome is to build ribosomes; to accomplish this task, ribosomes make ribosomal proteins, polymerases, enzymes, and signaling proteins. Every coded protein ever produced by life on Earth has passed through the exit tunnel, which is the birth canal of biology. During the root phase of the tree of life, before the last common ancestor of life (LUCA), exit tunnel evolution is dominant and unremitting. Protein folding coevolved with evolution of the exit tunnel. The ribosome shows that protein folding initiated with intrinsic disorder, supported through a short, primitive exit tunnel. Folding progressed to thermodynamically stable β-structures and then to kinetically trapped α-structures. The latter were enabled by a long, mature exit tunnel that partially offset the general thermodynamic tendency of all polypeptides to form β-sheets. RNA chaperoned the evolution of protein folding from the very beginning. The universal common core of the ribosome, with a mass of nearly 2 million Daltons, was finalized by LUCA. The ribosome entered stasis after LUCA and remained in that state for billions of years. Bacterial ribosomes never left stasis. Archaeal ribosomes have remained near stasis, except for the superphylum Asgard, which has accreted rRNA post LUCA. Eukaryotic ribosomes in some lineages appear to be logarithmically accreting rRNA over the last billion years. Ribosomal expansion in Asgard and Eukarya has been incremental and iterative, without substantial remodeling of pre-existing basal structures. The ribosome preserves information on its history.
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Affiliation(s)
- Jessica C Bowman
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Anton S Petrov
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Moran Frenkel-Pinter
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Petar I Penev
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Loren Dean Williams
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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11
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Mercier E, Wintermeyer W, Rodnina MV. Co-translational insertion and topogenesis of bacterial membrane proteins monitored in real time. EMBO J 2020; 39:e104054. [PMID: 32311161 PMCID: PMC7396858 DOI: 10.15252/embj.2019104054] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 01/23/2023] Open
Abstract
Integral membrane proteins insert into the bacterial inner membrane co‐translationally via the translocon. Transmembrane (TM) segments of nascent proteins adopt their native topological arrangement with the N‐terminus of the first TM (TM1) oriented to the outside (type I) or the inside (type II) of the cell. Here, we study TM1 topogenesis during ongoing translation in a bacterial in vitro system, applying real‐time FRET and protease protection assays. We find that TM1 of the type I protein LepB reaches the translocon immediately upon emerging from the ribosome. In contrast, the type II protein EmrD requires a longer nascent chain before TM1 reaches the translocon and adopts its topology by looping inside the ribosomal peptide exit tunnel. Looping presumably is mediated by interactions between positive charges at the N‐terminus of TM1 and negative charges in the tunnel wall. Early TM1 inversion is abrogated by charge reversal at the N‐terminus. Kinetic analysis also shows that co‐translational membrane insertion of TM1 is intrinsically rapid and rate‐limited by translation. Thus, the ribosome has an important role in membrane protein topogenesis.
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Affiliation(s)
- Evan Mercier
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Wolfgang Wintermeyer
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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12
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Nissley DA, Vu QV, Trovato F, Ahmed N, Jiang Y, Li MS, O'Brien EP. Electrostatic Interactions Govern Extreme Nascent Protein Ejection Times from Ribosomes and Can Delay Ribosome Recycling. J Am Chem Soc 2020; 142:6103-6110. [PMID: 32138505 DOI: 10.1021/jacs.9b12264] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The ejection of nascent proteins out of the ribosome exit tunnel, after their covalent bond to transfer-RNA has been broken, has not been experimentally studied due to challenges in sample preparation. Here, we investigate this process using a combination of multiscale modeling, ribosome profiling, and gene ontology analyses. Simulating the ejection of a representative set of 122 E. coli proteins we find a greater than 1000-fold variation in ejection times. Nascent proteins enriched in negatively charged residues near their C-terminus eject the fastest, while nascent chains enriched in positively charged residues tend to eject much more slowly. More work is required to pull slowly ejecting proteins out of the exit tunnel than quickly ejecting proteins, according to all-atom simulations. An energetic decomposition reveals, for slowly ejecting proteins, that this is due to the strong attractive electrostatic interactions between the nascent chain and the negatively charged ribosomal-RNA lining the exit tunnel, and for quickly ejecting proteins, it is due to their repulsive electrostatic interactions with the exit tunnel. Ribosome profiling data from E. coli reveals that the presence of slowly ejecting sequences correlates with ribosomes spending more time at stop codons, indicating that the ejection process might delay ribosome recycling. Proteins that have the highest positive charge density at their C-terminus are overwhelmingly ribosomal proteins, suggesting the possibility that this sequence feature may aid in the cotranslational assembly of ribosomes by delaying the release of nascent ribosomal proteins into the cytosol. Thus, nascent chain ejection times from the ribosome can vary greatly between proteins due to differential electrostatic interactions, can influence ribosome recycling, and could be particularly relevant to the synthesis and cotranslational behavior of some proteins.
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Affiliation(s)
| | - Quyen V Vu
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | | | | | | | - Mai Suan Li
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.,Institute for Computational Sciences and Technology, Ho Chi Minh City, Vietnam
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Cotranslational Folding of Proteins on the Ribosome. Biomolecules 2020; 10:biom10010097. [PMID: 31936054 PMCID: PMC7023365 DOI: 10.3390/biom10010097] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/20/2019] [Accepted: 12/25/2019] [Indexed: 02/04/2023] Open
Abstract
Many proteins in the cell fold cotranslationally within the restricted space of the polypeptide exit tunnel or at the surface of the ribosome. A growing body of evidence suggests that the ribosome can alter the folding trajectory in many different ways. In this review, we summarize the recent examples of how translation affects folding of single-domain, multiple-domain and oligomeric proteins. The vectorial nature of translation, the spatial constraints of the exit tunnel, and the electrostatic properties of the ribosome-nascent peptide complex define the onset of early folding events. The ribosome can facilitate protein compaction, induce the formation of intermediates that are not observed in solution, or delay the onset of folding. Examples of single-domain proteins suggest that early compaction events can define the folding pathway for some types of domain structures. Folding of multi-domain proteins proceeds in a domain-wise fashion, with each domain having its role in stabilizing or destabilizing neighboring domains. Finally, the assembly of protein complexes can also begin cotranslationally. In all these cases, the ribosome helps the nascent protein to attain a native fold and avoid the kinetic traps of misfolding.
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Kemp G, Kudva R, de la Rosa A, von Heijne G. Force-Profile Analysis of the Cotranslational Folding of HemK and Filamin Domains: Comparison of Biochemical and Biophysical Folding Assays. J Mol Biol 2019; 431:1308-1314. [DOI: 10.1016/j.jmb.2019.01.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/27/2019] [Accepted: 01/29/2019] [Indexed: 12/31/2022]
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