1
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Perlinska AP, Sikora M, Sulkowska JI. Everything AlphaFold tells us about protein knots. J Mol Biol 2024; 436:168715. [PMID: 39029890 DOI: 10.1016/j.jmb.2024.168715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/29/2024] [Accepted: 07/14/2024] [Indexed: 07/21/2024]
Abstract
Recent advances in Machine Learning methods in structural biology opened up new perspectives for protein analysis. Utilizing these methods allows us to go beyond the limitations of empirical research, and take advantage of the vast amount of generated data. We use a complete set of potentially knotted protein models identified in all high-quality predictions from the AlphaFold Database to search for any common trends that describe them. We show that the vast majority of knotted proteins have 31 knot and that the presence of knots is preferred in neither Bacteria, Eukaryota, or Archaea domains. On the contrary, the percentage of knotted proteins in any given proteome is around 0.4%, regardless of the taxonomical group. We also verified that the organism's living conditions do not impact the number of knotted proteins in its proteome, as previously expected. We did not encounter an organism without a single knotted protein. What is more, we found four universally present families of knotted proteins in Bacteria, consisting of SAM synthase, and TrmD, TrmH, and RsmE methyltransferases.
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Affiliation(s)
- Agata P Perlinska
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw 02-097, Poland
| | - Maciej Sikora
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw 02-097, Poland
| | - Joanna I Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw 02-097, Poland.
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2
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Alves Silva JC, Barden Grillo I, A Urquiza-Carvalho G, Bruno Rocha G. Exploring the electronic structure of knotted proteins: the case of two ornithine transcarbamylase family. J Mol Model 2024; 30:265. [PMID: 39008190 DOI: 10.1007/s00894-024-06009-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/06/2024] [Indexed: 07/16/2024]
Abstract
CONTEXT Geometrical knots are rare structural arrangements in proteins in which the polypeptide chain ties itself into a knot, which is very intriguing due to the uncertainty of their impact on the protein properties. Presently, classical molecular dynamics is the most employed technique in the few studies found on this topic, so any information on how the presence of knots affects the reactivity and electronic properties of proteins is even scarcer. Using the electronic structure methods and quantum chemical descriptors analysis, we found that the same amino-acid residues in the knot core have statistically larger values for the unknotted protein, for both hard-hard and soft-soft interaction descriptors. In addition, we present a computationally feasible protocol, where we show it is possible to separate the contribution of the geometrical knot to the reactivity and other electronic structure properties. METHODS In order to investigate these systems, we used PRIMoRDiA, a new software developed by our research group, to explore the electronic structure of biological macromolecules. We evaluated several local quantum chemical descriptors to unveil relevant patterns potentially originating from the presence of the geometrical knot in two proteins, belonging to the ornithine transcarbamylase family. We compared several sampled structures from these two enzymes that are highly similar in both tertiary structure and function, but one of them has a knot whereas the other does not. The sampling was carried out through molecular dynamics simulations using ff14SB force field along 50 ns, and the semiempirical convergence was performed with PM7 Hamiltonian.
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Affiliation(s)
- José Cícero Alves Silva
- Department of Chemistry, Federal University of Paraíba, Cid. Universitária, João Pessoa, 58051-900, Paraíba, Brazil
| | - Igor Barden Grillo
- Department of Chemistry, Federal University of Paraíba, Cid. Universitária, João Pessoa, 58051-900, Paraíba, Brazil
| | - Gabriel A Urquiza-Carvalho
- Department of Chemistry, Federal University of Pernambuco, Cid. Universitária, Recife, 50670-901, Pernambuco, Brazil
| | - Gerd Bruno Rocha
- Department of Chemistry, Federal University of Paraíba, Cid. Universitária, João Pessoa, 58051-900, Paraíba, Brazil.
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3
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Sikora M, Klimentova E, Uchal D, Sramkova D, Perlinska AP, Nguyen ML, Korpacz M, Malinowska R, Nowakowski S, Rubach P, Simecek P, Sulkowska JI. Knot or not? Identifying unknotted proteins in knotted families with sequence-based Machine Learning model. Protein Sci 2024; 33:e4998. [PMID: 38888487 PMCID: PMC11184937 DOI: 10.1002/pro.4998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 03/14/2024] [Accepted: 04/09/2024] [Indexed: 06/20/2024]
Abstract
Knotted proteins, although scarce, are crucial structural components of certain protein families, and their roles continue to be a topic of intense research. Capitalizing on the vast collection of protein structure predictions offered by AlphaFold (AF), this study computationally examines the entire UniProt database to create a robust dataset of knotted and unknotted proteins. Utilizing this dataset, we develop a machine learning (ML) model capable of accurately predicting the presence of knots in protein structures solely from their amino acid sequences. We tested the model's capabilities on 100 proteins whose structures had not yet been predicted by AF and found agreement with our local prediction in 92% cases. From the point of view of structural biology, we found that all potentially knotted proteins predicted by AF can be classified only into 17 families. This allows us to discover the presence of unknotted proteins in families with a highly conserved knot. We found only three new protein families: UCH, DUF4253, and DUF2254, that contain both knotted and unknotted proteins, and demonstrate that deletions within the knot core could potentially account for the observed unknotted (trivial) topology. Finally, we have shown that in the majority of knotted families (11 out of 15), the knotted topology is strictly conserved in functional proteins with very low sequence similarity. We have conclusively demonstrated that proteins AF predicts as unknotted are structurally accurate in their unknotted configurations. However, these proteins often represent nonfunctional fragments, lacking significant portions of the knot core (amino acid sequence).
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Affiliation(s)
- Maciej Sikora
- Centre of New Technologies, University of WarsawWarsawPoland
- Faculty of Mathematics, Informatics and Mechanics, University of WarsawWarsawPoland
| | - Eva Klimentova
- Central European Institute of Technology, Masaryk UniversityBrnoCzech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrnoCzech Republic
| | - Dawid Uchal
- Centre of New Technologies, University of WarsawWarsawPoland
- Faculty of Physics, University of WarsawWarsawPoland
| | - Denisa Sramkova
- Central European Institute of Technology, Masaryk UniversityBrnoCzech Republic
- National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrnoCzech Republic
| | | | - Mai Lan Nguyen
- Centre of New Technologies, University of WarsawWarsawPoland
| | - Marta Korpacz
- Centre of New Technologies, University of WarsawWarsawPoland
- Faculty of Mathematics, Informatics and Mechanics, University of WarsawWarsawPoland
| | - Roksana Malinowska
- Centre of New Technologies, University of WarsawWarsawPoland
- Faculty of Mathematics, Informatics and Mechanics, University of WarsawWarsawPoland
| | - Szymon Nowakowski
- Faculty of Mathematics, Informatics and Mechanics, University of WarsawWarsawPoland
- Faculty of Physics, University of WarsawWarsawPoland
| | - Pawel Rubach
- Centre of New Technologies, University of WarsawWarsawPoland
- Warsaw School of EconomicsWarsawPoland
| | - Petr Simecek
- Central European Institute of Technology, Masaryk UniversityBrnoCzech Republic
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4
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Perlinska AP, Nguyen ML, Pilla SP, Staszor E, Lewandowska I, Bernat A, Purta E, Augustyniak R, Bujnicki JM, Sulkowska JI. Are there double knots in proteins? Prediction and in vitro verification based on TrmD-Tm1570 fusion from C. nitroreducens. Front Mol Biosci 2024; 10:1223830. [PMID: 38903539 PMCID: PMC11187310 DOI: 10.3389/fmolb.2023.1223830] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/04/2023] [Indexed: 06/22/2024] Open
Abstract
We have been aware of the existence of knotted proteins for over 30 years-but it is hard to predict what is the most complicated knot that can be formed in proteins. Here, we show new and the most complex knotted topologies recorded to date-double trefoil knots (31 #31). We found five domain arrangements (architectures) that result in a doubly knotted structure in almost a thousand proteins. The double knot topology is found in knotted membrane proteins from the CaCA family, that function as ion transporters, in the group of carbonic anhydrases that catalyze the hydration of carbon dioxide, and in the proteins from the SPOUT superfamily that gathers 31 knotted methyltransferases with the active site-forming knot. For each family, we predict the presence of a double knot using AlphaFold and RoseTTaFold structure prediction. In the case of the TrmD-Tm1570 protein, which is a member of SPOUT superfamily, we show that it folds in vitro and is biologically active. Our results show that this protein forms a homodimeric structure and retains the ability to modify tRNA, which is the function of the single-domain TrmD protein. However, how the protein folds and is degraded remains unknown.
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Affiliation(s)
| | - Mai Lan Nguyen
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Polish-Japanese Academy of Information Technology, Warsaw, Poland
| | - Smita P. Pilla
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Emilia Staszor
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Chemistry, University of Warsaw, Warsaw, Poland
| | | | - Agata Bernat
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Elżbieta Purta
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | | | - Janusz M. Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
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5
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Niemyska W, Mukherjee S, Gren BA, Niewieczerzal S, Bujnicki JM, Sulkowska JI. Discovery of a trefoil knot in the RydC RNA: Challenging previous notions of RNA topology. J Mol Biol 2024; 436:168455. [PMID: 38272438 DOI: 10.1016/j.jmb.2024.168455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
Knots are very common in polymers, including DNA and protein molecules. Yet, no genuine knot has been identified in natural RNA molecules to date. Upon re-examining experimentally determined RNA 3D structures, we discovered a trefoil knot 31, the most basic non-trivial knot, in the RydC RNA. This knotted RNA is a member of a small family of short bacterial RNAs, whose secondary structure is characterized by an H-type pseudoknot. Molecular dynamics simulations suggest a folding pathway of the RydC RNA that starts with a native twisted loop. Based on sequence analyses and computational RNA 3D structure predictions, we postulate that this trefoil knot is a conserved feature of all RydC-related RNAs. The first discovery of a knot in a natural RNA molecule introduces a novel perspective on RNA 3D structure formation and on fundamental research on the relationship between function and spatial structure of biopolymers.
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Affiliation(s)
- Wanda Niemyska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland; Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland.
| | - Sunandan Mukherjee
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, 02-109 Warsaw, Poland
| | - Bartosz A Gren
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Szymon Niewieczerzal
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Trojdena 4, 02-109 Warsaw, Poland.
| | - Joanna I Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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6
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Sriramoju MK, Ko KT, Hsu STD. Tying a true topological protein knot by cyclization. Biochem Biophys Res Commun 2024; 696:149470. [PMID: 38244314 DOI: 10.1016/j.bbrc.2024.149470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 12/23/2023] [Accepted: 01/03/2024] [Indexed: 01/22/2024]
Abstract
Knotted proteins are fascinating to biophysicists because of their robust ability to fold into intricately defined three-dimensional structures with complex and topologically knotted arrangements. Exploring the biophysical properties of the knotted proteins is of significant interest, as they could offer enhanced chemical, thermal, and mechanostabilities. A true mathematical knot requires a closed path; in contrast, knotted protein structures have open N- and C-termini. To address the question of how a truly knotted protein differs from the naturally occurring counterpart, we enzymatically cyclized a 31 knotted YibK protein from Haemophilus influenza (HiYibK) to investigate the impact of path closure on its structure-function relationship and folding stability. Through the use of a multitude of structural and biophysical tools, including X-ray crystallography, NMR spectroscopy, small angle X-ray scattering, differential scanning calorimetry, and isothermal calorimetry, we showed that the path closure minimally perturbs the native structure and ligand binding of HiYibK. Nevertheless, the cyclization did alter the folding stability and mechanism according to chemical and thermal unfolding analysis. These molecular insights contribute to our fundamental understanding of protein folding and knotting that could have implications in the protein design with higher stabilities.
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Affiliation(s)
| | - Kuang-Ting Ko
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan
| | - Shang-Te Danny Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, 106319, Taiwan; International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM(2)), Hiroshima University, Higashihiroshima, 739-8527, Japan.
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7
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Lee J, Im D, Liu Y, Fang J, Tian X, Kim M, Zhang WB, Seo J. Distinguishing Protein Chemical Topologies Using Supercharging Ion Mobility Spectrometry-Mass Spectrometry. Angew Chem Int Ed Engl 2023; 62:e202314980. [PMID: 37937859 DOI: 10.1002/anie.202314980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/09/2023]
Abstract
A technique combining ion mobility spectrometry-mass spectrometry (IMS-MS) and supercharging electrospray ionization (ESI) has been demonstrated to differentiate protein chemical topology effectively. Incorporating as many charges as possible into proteins via supercharging ESI allows the protein chains to be largely unfolded and stretched, revealing their hidden chemical topology. Different chemical topologies result in differing geometrical sizes of the unfolded proteins due to constraints in torsional rotations in cyclic domains. By introducing new topological indices, such as the chain-length-normalized collision cross-section (CCS) and the maximum charge state (zM ) in the extensively unfolded state, we were able to successfully differentiate various protein chemical topologies, including linear chains, ring-containing topologies (lasso, tadpole, multicyclics, etc.), and mechanically interlocked rings, like catenanes.
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Affiliation(s)
- Jiyeon Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Gyeonsangbuk-do (Republic of, Korea
| | - Dahye Im
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Gyeonsangbuk-do (Republic of, Korea
| | - Yajie Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Jing Fang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Xibao Tian
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Minsu Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Gyeonsangbuk-do (Republic of, Korea
| | - Wen-Bin Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Jongcheol Seo
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 37673, Gyeonsangbuk-do (Republic of, Korea
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8
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Zayats V, Sikora M, Perlinska AP, Stasiulewicz A, Gren BA, Sulkowska JI. Conservation of knotted and slipknotted topology in transmembrane transporters. Biophys J 2023; 122:4528-4541. [PMID: 37919904 PMCID: PMC10719070 DOI: 10.1016/j.bpj.2023.10.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/25/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023] Open
Abstract
The existence of nontrivial topology is well accepted in globular proteins but not in membrane proteins. Our comprehensive topological analysis of the Protein Data Bank structures reveals 18 families of transmembrane proteins with nontrivial topology, showing that they constitute a significant number of membrane proteins. Moreover, we found that they comprise one of the largest groups of secondary active transporters. We classified them based on their knotted fingerprint into four groups: three slipknotted and one knotted. Unexpectedly, we found that the same protein can possess two distinct slipknot motifs that correspond to its outward- and inward-open conformational state. Based on the analysis of structures and knotted fingerprints, we show that slipknot topology is directly involved in the conformational transition and substrate transfer. Therefore, entanglement can be used to classify proteins and to find their structure-function relationship. Furthermore, based on the topological analysis of the transmembrane protein structures predicted by AlphaFold, we identified new potentially slipknotted protein families.
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Affiliation(s)
- Vasilina Zayats
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Maciej Sikora
- Centre of New Technologies, University of Warsaw, Warsaw, Poland; Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw, Poland
| | | | - Adam Stasiulewicz
- Centre of New Technologies, University of Warsaw, Warsaw, Poland; Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Warsaw, Poland
| | - Bartosz A Gren
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
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9
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Hsu STD. Folding and functions of knotted proteins. Curr Opin Struct Biol 2023; 83:102709. [PMID: 37778185 DOI: 10.1016/j.sbi.2023.102709] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 10/03/2023]
Abstract
Topologically knotted proteins have entangled structural elements within their native structures that cannot be disentangled simply by pulling from the N- and C-termini. Systematic surveys have identified different types of knotted protein structures, constituting as much as 1% of the total entries within the Protein Data Bank. Many knotted proteins rely on their knotted structural elements to carry out evolutionarily conserved biological functions. Being knotted may also provide mechanical stability to withstand unfolding-coupled proteolysis. Reconfiguring a knotted protein topology by circular permutation or cyclization provides insights into the importance of being knotted in the context of folding and functions. With the explosion of predicted protein structures by artificial intelligence, we are now entering a new era of exploring the entangled protein universe.
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Affiliation(s)
- Shang-Te Danny Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan; International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM(2)), Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
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10
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Salicari L, Baiesi M, Orlandini E, Trovato A. Folding kinetics of an entangled protein. PLoS Comput Biol 2023; 19:e1011107. [PMID: 37956216 PMCID: PMC10681328 DOI: 10.1371/journal.pcbi.1011107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 11/27/2023] [Accepted: 11/02/2023] [Indexed: 11/15/2023] Open
Abstract
The possibility of the protein backbone adopting lasso-like entangled motifs has attracted increasing attention. After discovering the surprising abundance of natively entangled protein domain structures, it was shown that misfolded entangled subpopulations might become thermosensitive or escape the homeostasis network just after translation. To investigate the role of entanglement in shaping folding kinetics, we introduce a novel indicator and analyze simulations of a coarse-grained, structure-based model for two small single-domain proteins. The model recapitulates the well-known two-state folding mechanism of a non-entangled SH3 domain. However, despite its small size, a natively entangled antifreeze RD1 protein displays a rich refolding behavior, populating two distinct kinetic intermediates: a short-lived, entangled, near-unfolded state and a longer-lived, non-entangled, near-native state. The former directs refolding along a fast pathway, whereas the latter is a kinetic trap, consistently with known experimental evidence of two different characteristic times. Upon trapping, the natively entangled loop folds without being threaded by the N-terminal residues. After trapping, the native entangled structure emerges by either backtracking to the unfolded state or threading through the already formed but not yet entangled loop. Along the fast pathway, trapping does not occur because the native contacts at the closure of the lasso-like loop fold after those involved in the N-terminal thread, confirming previous predictions. Despite this, entanglement may appear already in unfolded configurations. Remarkably, a longer-lived, near-native intermediate, with non-native entanglement properties, recalls what was observed in cotranslational folding.
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Affiliation(s)
- Leonardo Salicari
- Department of Physics and Astronomy “G. Galilei”, University of Padova, Padova, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Padova, Italy
| | - Marco Baiesi
- Department of Physics and Astronomy “G. Galilei”, University of Padova, Padova, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Padova, Italy
| | - Enzo Orlandini
- Department of Physics and Astronomy “G. Galilei”, University of Padova, Padova, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Padova, Italy
| | - Antonio Trovato
- Department of Physics and Astronomy “G. Galilei”, University of Padova, Padova, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Padova, Italy
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11
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Doyle LA, Takushi B, Kibler RD, Milles LF, Orozco CT, Jones JD, Jackson SE, Stoddard BL, Bradley P. De novo design of knotted tandem repeat proteins. Nat Commun 2023; 14:6746. [PMID: 37875492 PMCID: PMC10598012 DOI: 10.1038/s41467-023-42388-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 10/09/2023] [Indexed: 10/26/2023] Open
Abstract
De novo protein design methods can create proteins with folds not yet seen in nature. These methods largely focus on optimizing the compatibility between the designed sequence and the intended conformation, without explicit consideration of protein folding pathways. Deeply knotted proteins, whose topologies may introduce substantial barriers to folding, thus represent an interesting test case for protein design. Here we report our attempts to design proteins with trefoil (31) and pentafoil (51) knotted topologies. We extended previously described algorithms for tandem repeat protein design in order to construct deeply knotted backbones and matching designed repeat sequences (N = 3 repeats for the trefoil and N = 5 for the pentafoil). We confirmed the intended conformation for the trefoil design by X ray crystallography, and we report here on this protein's structure, stability, and folding behaviour. The pentafoil design misfolded into an asymmetric structure (despite a 5-fold symmetric sequence); two of the four repeat-repeat units matched the designed backbone while the other two diverged to form local contacts, leading to a trefoil rather than pentafoil knotted topology. Our results also provide insights into the folding of knotted proteins.
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Affiliation(s)
- Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Brittany Takushi
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA
| | - Ryan D Kibler
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - Lukas F Milles
- Department of Biochemistry, University of Washington, Seattle, WA, 98195, USA
| | - Carolina T Orozco
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Jonathan D Jones
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Sophie E Jackson
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA.
| | - Philip Bradley
- Division of Basic Sciences, Fred Hutchinson Cancer Center, 1100 Fairview Ave. North, Seattle, WA, 98109, USA.
- Division of Public Health Sciences and Program in Computational Biology, Fred Hutchinson Cancer Center, 1100 Fairview Ave. N, Seattle, WA, 98009, USA.
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12
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Jedrzejewski M, Belza B, Lewandowska I, Sadlej M, Perlinska AP, Augustyniak R, Christian T, Hou YM, Kalek M, Sulkowska JI. Nucleolar Essential Protein 1 (Nep1): Elucidation of enzymatic catalysis mechanism by molecular dynamics simulation and quantum mechanics study. Comput Struct Biotechnol J 2023; 21:3999-4008. [PMID: 37649713 PMCID: PMC10462857 DOI: 10.1016/j.csbj.2023.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 09/01/2023] Open
Abstract
The Nep1 protein is essential for the formation of eukaryotic and archaeal small ribosomal subunits, and it catalyzes the site-directed SAM-dependent methylation of pseudouridine (Ψ) during pre-rRNA processing. It possesses a non-trivial topology, namely, a 31 knot in the active site. Here, we address the issue of seemingly unfeasible deprotonation of Ψ in Nep1 active site by a distant aspartate residue (D101 in S. cerevisiae), using a combination of bioinformatics, computational, and experimental methods. We identified a conserved hydroxyl-containing amino acid (S233 in S. cerevisiae, T198 in A. fulgidus) that may act as a proton-transfer mediator. Molecular dynamics simulations, based on the crystal structure of S. cerevisiae, and on a complex generated by molecular docking in A. fulgidus, confirmed that this amino acid can shuttle protons, however, a water molecule in the active site may also serve this role. Quantum-chemical calculations based on density functional theory and the cluster approach showed that the water-mediated pathway is the most favorable for catalysis. Experimental kinetic and mutational studies reinforce the requirement for the aspartate D101, but not S233. These findings provide insight into the catalytic mechanisms underlying proton transfer over extended distances and comprehensively elucidate the mode of action of Nep1.
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Affiliation(s)
- Mateusz Jedrzejewski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Barbara Belza
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Iwona Lewandowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Marta Sadlej
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Agata P. Perlinska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Rafal Augustyniak
- Department of Chemistry, University of Warsaw, Ludwika Pasteura 1, 02-093, Warsaw, Poland
| | - Thomas Christian
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 4201 Henry Ave, Philadelphia, PA 19144, USA
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 4201 Henry Ave, Philadelphia, PA 19144, USA
| | - Marcin Kalek
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Joanna I. Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
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13
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Ozmaian M, Makarov DE. Long-lived metastable knots in polyampholyte chains. PLoS One 2023; 18:e0287200. [PMID: 37315055 PMCID: PMC10266668 DOI: 10.1371/journal.pone.0287200] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/31/2023] [Indexed: 06/16/2023] Open
Abstract
Knots in proteins and DNA are known to have significant effect on their equilibrium and dynamic properties as well as on their function. While knot dynamics and thermodynamics in electrically neutral and uniformly charged polymer chains are relatively well understood, proteins are generally polyampholytes, with varied charge distributions along their backbones. Here we use simulations of knotted polymer chains to show that variation in the charge distribution on a polyampholyte chain with zero net charge leads to significant variation in the resulting knot dynamics, with some charge distributions resulting in long-lived metastable knots that escape the (open-ended) chain on a timescale that is much longer than that for knots in electrically neutral chains. The knot dynamics in such systems can be described, quantitatively, using a simple one-dimensional model where the knot undergoes biased Brownian motion along a "reaction coordinate", equal to the knot size, in the presence of a potential of mean force. In this picture, long-lived knots result from charge sequences that create large electrostatic barriers to knot escape. This model allows us to predict knot lifetimes even when those times are not directly accessible by simulations.
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Affiliation(s)
- Masoumeh Ozmaian
- College of Engineering, West Texas A&M University, Canyon, Texas, United States of America
| | - Dmitrii E. Makarov
- Department of Chemistry, University of Texas at Austin, Austin, Texas, United States of America
- Oden Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas, United States of America
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14
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Salicari L, Trovato A. Entangled Motifs in Membrane Protein Structures. Int J Mol Sci 2023; 24:ijms24119193. [PMID: 37298146 DOI: 10.3390/ijms24119193] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Entangled motifs are found in one-third of protein domain structures, a reference set that contains mostly globular proteins. Their properties suggest a connection with co-translational folding. Here, we wish to investigate the presence and properties of entangled motifs in membrane protein structures. From existing databases, we build a non-redundant data set of membrane protein domains, annotated with the monotopic/transmembrane and peripheral/integral labels. We evaluate the presence of entangled motifs using the Gaussian entanglement indicator. We find that entangled motifs appear in one-fifth of transmembrane and one-fourth of monotopic proteins. Surprisingly, the main features of the distribution of the values of the entanglement indicator are similar to the reference case of general proteins. The distribution is conserved across different organisms. Differences with respect to the reference set emerge when considering the chirality of entangled motifs. Although the same chirality bias is found for single-winding motifs in both membrane and reference proteins, the bias is reversed, strikingly, for double-winding motifs only in the reference set. We speculate that these observations can be rationalized in terms of the constraints exerted on the nascent chain by the co-translational bio-genesis machinery, which is different for membrane and globular proteins.
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Affiliation(s)
- Leonardo Salicari
- Department of Physics and Astronomy 'Galileo Galilei', University of Padova, Via Marzolo 8, 35031 Padova, PD, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Via Marzolo 8, 35131 Padova, PD, Italy
| | - Antonio Trovato
- Department of Physics and Astronomy 'Galileo Galilei', University of Padova, Via Marzolo 8, 35031 Padova, PD, Italy
- National Institute of Nuclear Physics (INFN), Padova Section, Via Marzolo 8, 35131 Padova, PD, Italy
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15
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Zhao Y, Rothörl J, Besenius P, Virnau P, Daoulas KC. Can Polymer Helicity Affect Topological Chirality of Polymer Knots? ACS Macro Lett 2023; 12:234-240. [PMID: 36706453 PMCID: PMC9948535 DOI: 10.1021/acsmacrolett.2c00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We investigate the effect of helicity in isolated polymers on the topological chirality of their knots with computer simulations. Polymers are described by generic worm-like chains (WLC), where helical conformations are promoted by chiral coupling between segments that are neighbors along the chain contour. The sign and magnitude of the coupling coefficient u determine the sense and strength of helicity. The corrugation of the helix is adjusted via the radius R of a spherical, hard excluded volume around each WLC segment. Open and compact helices are, respectively, obtained for R that is either zero or smaller than the length of the WLC bond, and R that is a few times larger than the bond length. We use a Monte Carlo algorithm to sample polymer conformations for different values of u, spanning the range from achiral polymers to chains with well-developed helices. Monitoring the average helix torsion and fluctuations of chiral order as a function of u, for two very different chain lengths, demonstrates that the coil-helix transition in this model is not a phase transition but a crossover. Statistical analysis of conformations forming the simplest chiral knots, 31, 51, and 52, demonstrates that topological mirror symmetry is broken─knots formed by helices with a given sense prefer one handedness over the other. For the 31 and 51 knots, positive helical sense favors positive handedness. Intriguingly, an opposite trend is observed for 52 knots, where positive helical sense promotes negative handedness. We argue that this special coupling between helicity and topological chirality stems from a generic mechanism: conformations where some of the knot crossings are found in "braids" formed by two tightly interwoven sections of the polymer.
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Affiliation(s)
- Yani Zhao
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Jan Rothörl
- Department
of Physics, Johannes Gutenberg University
Mainz, Staudingerweg 9, 55128 Mainz, Germany
| | - Pol Besenius
- Department
of Chemistry, Johannes Gutenberg University
Mainz, Duesbergweg 10-14, 55128 Mainz, Germany
| | - Peter Virnau
- Department
of Physics, Johannes Gutenberg University
Mainz, Staudingerweg 9, 55128 Mainz, Germany,E-mail:
| | - Kostas Ch. Daoulas
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany,E-mail: . Phone: +49
(0)6131 379218
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16
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Tagliabue A, Micheletti C, Mella M. Tuning Knotted Copolyelectrolyte Conformations via Solution Properties. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- Andrea Tagliabue
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100Como, Italy
- SISSA (Scuola Internazionale Superiore di Studi Avanzati), via Bonomea 265, 34136Trieste, Italy
| | - Cristian Micheletti
- SISSA (Scuola Internazionale Superiore di Studi Avanzati), via Bonomea 265, 34136Trieste, Italy
| | - Massimo Mella
- Dipartimento di Scienza ed Alta Tecnologia, Università degli Studi dell’Insubria, via Valleggio 11, 22100Como, Italy
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17
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Brems MA, Runkel R, Yeates TO, Virnau P. AlphaFold
predicts the most complex protein knot and composite protein knots. Protein Sci 2022; 31:e4380. [PMID: 35900026 PMCID: PMC9278004 DOI: 10.1002/pro.4380] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 11/06/2022]
Abstract
The computer artificial intelligence system AlphaFold has recently predicted previously unknown three‐dimensional structures of thousands of proteins. Focusing on the subset with high‐confidence scores, we algorithmically analyze these predictions for cases where the protein backbone exhibits rare topological complexity, that is, knotting. Amongst others, we discovered a 71‐knot, the most topologically complex knot ever found in a protein, as well several six‐crossing composite knots comprised of two methyltransferase or carbonic anhydrase domains, each containing a simple trefoil knot. These deeply embedded composite knots occur evidently by gene duplication and interconnection of knotted dimers. Finally, we report two new five‐crossing knots including the first 51‐knot. Our list of analyzed structures forms the basis for future experimental studies to confirm these novel‐knotted topologies and to explore their complex folding mechanisms.
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Affiliation(s)
- Maarten A. Brems
- Department of Physics Johannes Gutenberg University Mainz Mainz Germany
| | - Robert Runkel
- Department of Physics Johannes Gutenberg University Mainz Mainz Germany
| | - Todd O. Yeates
- UCLA‐DOE Institute for Genomics and Proteomics University of California Los Angeles Los Angeles California USA
- UCLA Department of Chemistry and Biochemistry University of California Los Angeles Los Angeles California USA
| | - Peter Virnau
- Department of Physics Johannes Gutenberg University Mainz Mainz Germany
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18
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Niemyska W, Rubach P, Gren BA, Nguyen ML, Garstka W, Bruno da Silva F, Rawdon EJ, Sulkowska JI. AlphaKnot: server to analyze entanglement in structures predicted by AlphaFold methods. Nucleic Acids Res 2022; 50:W44-W50. [PMID: 35609987 PMCID: PMC9252816 DOI: 10.1093/nar/gkac388] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/20/2022] [Accepted: 05/06/2022] [Indexed: 11/25/2022] Open
Abstract
AlphaKnot is a server that measures entanglement in AlphaFold-solved protein models while considering pLDDT confidence values. AlphaKnot has two main functions: (i) providing researchers with a webserver for analyzing knotting in their own AlphaFold predictions and (ii) providing a database of knotting in AlphaFold predictions from the 21 proteomes for which models have been published prior to 2022. The knotting is defined in a probabilistic fashion. The knotting complexity of proteins is presented in the form of a matrix diagram which shows users the knot type for the entire polypeptide chain and for each of its subchains. The dominant knot types as well as the computed locations of the knot cores (i.e. minimal portions of protein backbones that form a given knot type) are shown for each protein structure. Based mainly on the pLDDT confidence values, entanglements are classified as Knots, Unsure, and Artifacts. The database portion of the server can be used, for example, to examine protein geometry and entanglement-function correlations, as a reference set for protein modeling, and for facilitating evolutional studies. The AlphaKnot server can be found at https://alphaknot.cent.uw.edu.pl/.
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Affiliation(s)
- Wanda Niemyska
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland.,Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Pawel Rubach
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland.,Warsaw School of Economics,Al. Niepodleglosci 162, 02-554, Warsaw, Poland
| | - Bartosz A Gren
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland
| | - Mai Lan Nguyen
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland.,Polish-Japanese Academy of Information Technology, Koszykowa 86, 02-008 Warsaw, Poland
| | - Wojciech Garstka
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland.,Inter-faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | | | - Eric J Rawdon
- University of St. Thomas, 2115 Summit Ave, Saint Paul, MN 55105, USA
| | - Joanna I Sulkowska
- Centre of New Technologies, University of Warsaw, Banacha 2c, Warsaw, Poland
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19
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Blackholly LR, Harris NJ, Findlay HE, Booth PJ. Cell-Free Expression to Probe Co-Translational Insertion of an Alpha Helical Membrane Protein. Front Mol Biosci 2022; 9:795212. [PMID: 35187078 PMCID: PMC8847741 DOI: 10.3389/fmolb.2022.795212] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/11/2022] [Indexed: 01/23/2023] Open
Abstract
The majority of alpha helical membrane proteins fold co-translationally during their synthesis on the ribosome. In contrast, most mechanistic folding studies address refolding of full-length proteins from artificially induced denatured states that are far removed from the natural co-translational process. Cell-free translation of membrane proteins is emerging as a useful tool to address folding during translation by a ribosome. We summarise the benefits of this approach and show how it can be successfully extended to a membrane protein with a complex topology. The bacterial leucine transporter, LeuT can be synthesised and inserted into lipid membranes using a variety of in vitro transcription translation systems. Unlike major facilitator superfamily transporters, where changes in lipids can optimise the amount of correctly inserted protein, LeuT insertion yields are much less dependent on the lipid composition. The presence of a bacterial translocon either in native membrane extracts or in reconstituted membranes also has little influence on the yield of LeuT incorporated into the lipid membrane, except at high reconstitution concentrations. LeuT is considered a paradigm for neurotransmitter transporters and possesses a knotted structure that is characteristic of this transporter family. This work provides a method in which to probe the formation of a protein as the polypeptide chain is being synthesised on a ribosome and inserting into lipids. We show that in comparison with the simpler major facilitator transporter structures, LeuT inserts less efficiently into membranes when synthesised cell-free, suggesting that more of the protein aggregates, likely as a result of the challenging formation of the knotted topology in the membrane.
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Affiliation(s)
| | | | | | - Paula J. Booth
- Department of Chemistry, King’s College London, London, United Kingdom
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20
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Wang J, Peng X. In silico method for identifying the key residues in a knotted protein: with MJ0366 as an example. Phys Chem Chem Phys 2022; 24:27495-27504. [DOI: 10.1039/d2cp03589h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A simple in silico method for predicting the key residues for knotting and unknotting a knotted protein is put forward, with the residues ranked by the relevance to knotting and unknotting in the annealing molecular dynamics simulations.
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Affiliation(s)
- Jianmei Wang
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Xubiao Peng
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
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21
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Wu WH, Bai X, Shao Y, Yang C, Wei J, Wei W, Zhang WB. Higher Order Protein Catenation Leads to an Artificial Antibody with Enhanced Affinity and In Vivo Stability. J Am Chem Soc 2021; 143:18029-18040. [PMID: 34664942 DOI: 10.1021/jacs.1c06169] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The chemical topology is a unique dimension for protein engineering, yet the topological diversity and architectural complexity of proteins remain largely untapped. Herein, we report the biosynthesis of complex topological proteins using a rationally engineered, cross-entwining peptide heterodimer motif derived from p53dim (an entangled homodimeric mutant of the tetramerization domain of the tumor suppressor protein p53). The incorporation of an electrostatic interaction at specific sites converts the p53dim homodimer motif into a pair of heterodimer motifs with high specificity for directing chain entanglement upon folding. Its combination with split-intein-mediated ligation and/or SpyTag/SpyCatcher chemistry facilitates the programmed synthesis of protein heterocatenane or [n]catenanes in cells, leading to a general and modular approach to complex protein catenanes containing various proteins of interest. Concatenation enhances not only the target protein's affinity but also the in vivo stability as shown by its prolonged circulation time in blood. As a proof of concept, artificial antibodies have been developed by embedding a human epidermal growth factor receptor 2-specific affibody onto the [n]catenane scaffolds and shown to exhibit a higher affinity and a better pharmacokinetic profile than the wild-type affibody. These results suggest that topology engineering holds great promise in the development of therapeutic proteins.
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Affiliation(s)
- Wen-Hao Wu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Xilin Bai
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Yu Shao
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
| | - Chao Yang
- College of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, P. R. China
| | - Jingjing Wei
- College of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, P. R. China
| | - Wei Wei
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Wen-Bin Zhang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
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22
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Slipknotted and unknotted monovalent cation-proton antiporters evolved from a common ancestor. PLoS Comput Biol 2021; 17:e1009502. [PMID: 34648493 PMCID: PMC8562792 DOI: 10.1371/journal.pcbi.1009502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/02/2021] [Accepted: 09/28/2021] [Indexed: 11/20/2022] Open
Abstract
While the slipknot topology in proteins has been known for over a decade, its evolutionary origin is still a mystery. We have identified a previously overlooked slipknot motif in a family of two-domain membrane transporters. Moreover, we found that these proteins are homologous to several families of unknotted membrane proteins. This allows us to directly investigate the evolution of the slipknot motif. Based on our comprehensive analysis of 17 distantly related protein families, we have found that slipknotted and unknotted proteins share a common structural motif. Furthermore, this motif is conserved on the sequential level as well. Our results suggest that, regardless of topology, the proteins we studied evolved from a common unknotted ancestor single domain protein. Our phylogenetic analysis suggests the presence of at least seven parallel evolutionary scenarios that led to the current diversity of proteins in question. The tools we have developed in the process can now be used to investigate the evolution of other repeated-domain proteins. In proteins with the slipknot topology, the polypeptide chain forms a slipknot—a structure that is not necessarily manifest to a naked eye, but it can be detected using mathematical methods. Slipknots are conserved motifs often found at catalytic sites and are directly involved in molecular transport. Although the first proteins with slipknots were found in 2007, many questions remain unanswered, e.g. how these proteins appeared, or whether the slipknotted proteins evolved from unknotted ones or vice versa. Here we provide the first analysis of homologous slipknotted and unknotted transmembrane proteins in order to elucidate their evolutionary relationship. We show that two-domain slipknotted and unknotted membrane transporters share the same one-domain unknotted protein as an ancestor. The ancestor gene duplicated and underwent various diversification and fusion events during the evolution, which have led to the appearance of a large superfamily of secondary active transporters. The slipknot motif seems to have been created by chance after a fusion of two single domain genes. Therefore, we show here that the slipknotted transporter evolved from an unknotted one-domain protein and that there are at least seven different evolutionary scenarios that gave rise to this large superfamily of transporters.
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23
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Hsu STD, Lee YTC, Mikula KM, Backlund SM, Tascón I, Goldman A, Iwaï H. Tying up the Loose Ends: A Mathematically Knotted Protein. Front Chem 2021; 9:663241. [PMID: 34109153 PMCID: PMC8182377 DOI: 10.3389/fchem.2021.663241] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/20/2021] [Indexed: 11/23/2022] Open
Abstract
Knots have attracted scientists in mathematics, physics, biology, and engineering. Long flexible thin strings easily knot and tangle as experienced in our daily life. Similarly, long polymer chains inevitably tend to get trapped into knots. Little is known about their formation or function in proteins despite >1,000 knotted proteins identified in nature. However, these protein knots are not mathematical knots with their backbone polypeptide chains because of their open termini, and the presence of a “knot” depends on the algorithm used to create path closure. Furthermore, it is generally not possible to control the topology of the unfolded states of proteins, therefore making it challenging to characterize functional and physicochemical properties of knotting in any polymer. Covalently linking the amino and carboxyl termini of the deeply trefoil-knotted YibK from Pseudomonas aeruginosa allowed us to create the truly backbone knotted protein by enzymatic peptide ligation. Moreover, we produced and investigated backbone cyclized YibK without any knotted structure. Thus, we could directly probe the effect of the backbone knot and the decrease in conformational entropy on protein folding. The backbone cyclization did not perturb the native structure and its cofactor binding affinity, but it substantially increased the thermal stability and reduced the aggregation propensity. The enhanced stability of a backbone knotted YibK could be mainly originated from an increased ruggedness of its free energy landscape and the destabilization of the denatured state by backbone cyclization with little contribution from a knot structure. Despite the heterogeneity in the side-chain compositions, the chemically unfolded cyclized YibK exhibited several macroscopic physico-chemical attributes that agree with theoretical predictions derived from polymer physics.
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Affiliation(s)
- Shang-Te Danny Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Yun-Tzai Cloud Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.,Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Kornelia M Mikula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Sofia M Backlund
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Igor Tascón
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Adrian Goldman
- Division of Biochemistry, Department of Biosciences, University of Helsinki, Helsinki, Finland.,Astbury Centre for Structural Molecular Biology, School of Biomedical Sciences, University of Leeds, West Yorkshire, United Kingdom
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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24
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Paissoni C, Puri S, Wang I, Chen SY, Camilloni C, Hsu STD. Converging experimental and computational views of the knotting mechanism of a small knotted protein. Biophys J 2021; 120:2276-2286. [PMID: 33812848 PMCID: PMC8390826 DOI: 10.1016/j.bpj.2021.03.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/14/2021] [Accepted: 03/29/2021] [Indexed: 01/18/2023] Open
Abstract
MJ0366 from Methanocaldococcus jannaschii is the smallest topologically knotted protein known to date. 92 residues in length, MJ0366 ties a trefoil (31) knot by threading its C-terminal helix through a buttonhole formed by the remainder of the secondary structure elements. By generating a library of point mutations at positions pertinent to the knot formation, we systematically evaluated the contributions of individual residues to the folding stability and kinetics of MJ0366. The experimental Φ-values were used as restraints to computationally generate an ensemble of conformations that correspond to the transition state of MJ0366, which revealed several nonnative contacts. The importance of these nonnative contacts in stabilizing the transition state of MJ0366 was confirmed by a second round of mutagenesis, which also established the pivotal role of F15 in stapling the network of hydrophobic interactions around the threading C-terminal helix. Our converging experimental and computational results show that, despite the small size, the transition state of MJ0366 is formed at a very late stage of the folding reaction coordinate, following a polarized pathway. Eventually, the formation of extensive native contacts, as well as a number of nonnative ones, leads to the threading of the C-terminal helix that defines the topological knot.
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Affiliation(s)
- Cristina Paissoni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy
| | - Sarita Puri
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Iren Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Szu-Yu Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Carlo Camilloni
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy.
| | - Shang-Te Danny Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
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25
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Abstract
We investigate aspects of topology in protein folding. For this we numerically simulate the temperature driven folding and unfolding of the slipknotted archaeal virus protein AFV3-109. Due to knottiness the (un)folding is a topological process, it engages the entire backbone in a collective fashion. Accordingly we introduce a topological approach to model the process. Our simulations reveal that the (un)folding of AFV3-109 slipknot proceeds through a folding intermediate that has the topology of a trefoil knot. We observe that the final slipknot causes a slight swelling of the folded AFV3-109 structure. We disclose the relative stability of the strands and helices during both the folding and unfolding processes. We confirm results from previous studies that pointed out that it can be very demanding to simulate the formation of knotty self-entanglement, and we explain how the problems are circumvented: The slipknotted AFV3-109 protein is a very slow folder with a topologically demanding pathway, which needs to be properly accounted for in a simulation description. When we either increase the relative stiffness of bending, or when we decrease the speed of ambient cooling, the rate of slipknot formation rapidly increases.
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Piejko M, Niewieczerzal S, Sulkowska JI. The Folding of Knotted Proteins: Distinguishing the Distinct Behavior of Shallow and Deep Knots. Isr J Chem 2020. [DOI: 10.1002/ijch.202000036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Maciej Piejko
- Faculty of ChemistryUniversity of Warsaw Pasteura 1 Warsaw 02-093 Poland
- Centre of New TechnologiesUniversity of Warsaw Banacha 2c Warsaw 02-097 Poland
| | | | - Joanna I. Sulkowska
- Faculty of ChemistryUniversity of Warsaw Pasteura 1 Warsaw 02-093 Poland
- Centre of New TechnologiesUniversity of Warsaw Banacha 2c Warsaw 02-097 Poland
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Sulkowska JI. On folding of entangled proteins: knots, lassos, links and θ-curves. Curr Opin Struct Biol 2020; 60:131-141. [PMID: 32062143 DOI: 10.1016/j.sbi.2020.01.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/02/2020] [Accepted: 01/12/2020] [Indexed: 12/15/2022]
Abstract
Around 6% of protein structures deposited in the PDB are entangled, forming knots, slipknots, lassos, links, and θ-curves. In each of these cases, the protein backbone weaves through itself in a complex way, and at some point passes through a closed loop, formed by other regions of the protein structure. Such a passing can be interpreted as crossing a topological barrier. How proteins overcome such barriers, and therefore different degrees of frustration, challenged scientists and has shed new light on the field of protein folding. In this review, we summarize the current knowledge about the free energy landscape of proteins with non-trivial topology. We describe identified mechanisms which lead proteins to self-tying. We discuss the influence of excluded volume, such as crowding and chaperones, on tying, based on available data. We briefly discuss the diversity of topological complexity of proteins and their evolution. We also list available tools to investigate non-trivial topology. Finally, we formulate intriguing and challenging questions at the boundary of biophysics, bioinformatics, biology, and mathematics, which arise from the discovery of entangled proteins.
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Affiliation(s)
- Joanna Ida Sulkowska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland; Faculty of Chemistry, University of Warsaw, Warsaw, Poland.
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28
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Norbiato F, Seno F, Trovato A, Baiesi M. Folding Rate Optimization Promotes Frustrated Interactions in Entangled Protein Structures. Int J Mol Sci 2019; 21:ijms21010213. [PMID: 31892272 PMCID: PMC6981561 DOI: 10.3390/ijms21010213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/16/2019] [Accepted: 12/25/2019] [Indexed: 12/15/2022] Open
Abstract
Many native structures of proteins accomodate complex topological motifs such as knots, lassos, and other geometrical entanglements. How proteins can fold quickly even in the presence of such topological obstacles is a debated question in structural biology. Recently, the hypothesis that energetic frustration might be a mechanism to avoid topological frustration has been put forward based on the empirical observation that loops involved in entanglements are stabilized by weak interactions between amino-acids at their extrema. To verify this idea, we use a toy lattice model for the folding of proteins into two almost identical structures, one entangled and one not. As expected, the folding time is longer when random sequences folds into the entangled structure. This holds also under an evolutionary pressure simulated by optimizing the folding time. It turns out that optmized protein sequences in the entangled structure are in fact characterized by frustrated interactions at the closures of entangled loops. This phenomenon is much less enhanced in the control case where the entanglement is not present. Our findings, which are in agreement with experimental observations, corroborate the idea that an evolutionary pressure shapes the folding funnel to avoid topological and kinetic traps.
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Affiliation(s)
- Federico Norbiato
- Department of Physics and Astronomy, University of Padova, Via Marzolo 8, I-35131 Padova, Italy; (F.N.); (F.S.); (A.T.)
| | - Flavio Seno
- Department of Physics and Astronomy, University of Padova, Via Marzolo 8, I-35131 Padova, Italy; (F.N.); (F.S.); (A.T.)
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
| | - Antonio Trovato
- Department of Physics and Astronomy, University of Padova, Via Marzolo 8, I-35131 Padova, Italy; (F.N.); (F.S.); (A.T.)
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
| | - Marco Baiesi
- Department of Physics and Astronomy, University of Padova, Via Marzolo 8, I-35131 Padova, Italy; (F.N.); (F.S.); (A.T.)
- INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova, Italy
- Correspondence:
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Jarmolinska AI, Gambin A, Sulkowska JI. Knot_pull-python package for biopolymer smoothing and knot detection. Bioinformatics 2019; 36:953-955. [PMID: 31504154 PMCID: PMC9883683 DOI: 10.1093/bioinformatics/btz644] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/08/2019] [Accepted: 08/13/2019] [Indexed: 02/03/2023] Open
Abstract
SUMMARY The biggest hurdle in studying topology in biopolymers is the steep learning curve for actually seeing the knots in structure visualization. Knot_pull is a command line utility designed to simplify this process-it presents the user with a smoothing trajectory for provided structures (any number and length of protein, RNA or chromatin chains in PDB, CIF or XYZ format), and calculates the knot type (including presence of any links, and slipknots when a subchain is specified). AVAILABILITY AND IMPLEMENTATION Knot_pull works under Python >=2.7 and is system independent. Source code and documentation are available at http://github.com/dzarmola/knot_pull under GNU GPL license and include also a wrapper script for PyMOL for easier visualization. Examples of smoothing trajectories can be found at: https://www.youtube.com/watch?v=IzSGDfc1vAY. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
| | - Anna Gambin
- Department of Mathematics, Informatics and Mechanics, University of Warsaw, Warsaw 02-097, Poland
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30
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Da X, Zhang W. Active Template Synthesis of Protein Heterocatenanes. Angew Chem Int Ed Engl 2019; 58:11097-11104. [DOI: 10.1002/anie.201904943] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Xiao‐Di Da
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Polymer Chemistry & Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
| | - Wen‐Bin Zhang
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Polymer Chemistry & Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
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31
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Ko KT, Hu IC, Huang KF, Lyu PC, Hsu STD. Untying a Knotted SPOUT RNA Methyltransferase by Circular Permutation Results in a Domain-Swapped Dimer. Structure 2019; 27:1224-1233.e4. [DOI: 10.1016/j.str.2019.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/01/2019] [Accepted: 04/05/2019] [Indexed: 11/28/2022]
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Affiliation(s)
- Xiao‐Di Da
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Polymer Chemistry & Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
| | - Wen‐Bin Zhang
- Beijing National Laboratory for Molecular SciencesKey Laboratory of Polymer Chemistry & Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking University Beijing 100871 P. R. China
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