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Leikina E, Whitlock JM, Melikov K, Zhang W, Bachmann MP, Chernomordik LV. Formation of Multinucleated Osteoclasts Depends on an Oxidized Species of Cell Surface Associated La Protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592254. [PMID: 38903088 PMCID: PMC11188106 DOI: 10.1101/2024.05.02.592254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated osteoclasts are formed by the fusion of precursor cells, and larger cells - generated by an increased number of cell fusion events - have higher resorptive activity. We find that osteoclast fusion and bone-resorption are promoted by reactive oxygen species (ROS) signaling and by an unconventional low molecular weight species of La protein, located at the osteoclast surface. Here, we develop the hypothesis that La's unique regulatory role in osteoclast multinucleation and function is controlled by a ROS switch in La trafficking. Using antibodies that recognize reduced or oxidized species of La, we find that differentiating osteoclasts enrich an oxidized species of La at the cell surface, which is distinct from the reduced La species conventionally localized within cell nuclei. ROS signaling triggers the shift from reduced to oxidized La species, its dephosphorylation and delivery to the surface of osteoclasts, where La promotes multinucleation and resorptive activity. Moreover, intracellular ROS signaling in differentiating osteoclasts oxidizes critical cysteine residues in the C-terminal half of La, producing this unconventional La species that promotes osteoclast fusion. Our findings suggest that redox signaling induces changes in the location and function of La and may represent a promising target for novel skeletal therapies.
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2
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Porter LL, Artsimovitch I, Ramírez-Sarmiento CA. Metamorphic proteins and how to find them. Curr Opin Struct Biol 2024; 86:102807. [PMID: 38537533 PMCID: PMC11102287 DOI: 10.1016/j.sbi.2024.102807] [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: 02/01/2024] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
In the last two decades, our existing notion that most foldable proteins have a unique native state has been challenged by the discovery of metamorphic proteins, which reversibly interconvert between multiple, sometimes highly dissimilar, native states. As the number of known metamorphic proteins increases, several computational and experimental strategies have emerged for gaining insights about their refolding processes and identifying unknown metamorphic proteins amongst the known proteome. In this review, we describe the current advances in biophysically and functionally ascertaining the structural interconversions of metamorphic proteins and how coevolution can be harnessed to identify novel metamorphic proteins from sequence information. We also discuss the challenges and ongoing efforts in using artificial intelligence-based protein structure prediction methods to discover metamorphic proteins and predict their corresponding three-dimensional structures.
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Affiliation(s)
- Lauren L Porter
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA; Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Irina Artsimovitch
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile; ANID, Millennium Science Initiative Program, Millennium Institute for Integrative Biology (iBio), Santiago 833150, Chile.
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3
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Zhang N, Sood D, Guo SC, Chen N, Antoszewski A, Marianchuk T, Chavan A, Dey S, Xiao Y, Hong L, Peng X, Baxa M, Partch C, Wang LP, Sosnick TR, Dinner AR, LiWang A. Temperature-Dependent Fold-Switching Mechanism of the Circadian Clock Protein KaiB. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.21.594594. [PMID: 38826295 PMCID: PMC11142059 DOI: 10.1101/2024.05.21.594594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The oscillator of the cyanobacterial circadian clock relies on the ability of the KaiB protein to switch reversibly between a stable ground-state fold (gsKaiB) and an unstable fold-switched fold (fsKaiB). Rare fold-switching events by KaiB provide a critical delay in the negative feedback loop of this post-translational oscillator. In this study, we experimentally and computationally investigate the temperature dependence of fold switching and its mechanism. We demonstrate that the stability of gsKaiB increases with temperature compared to fsKaiB and that the Q10 value for the gsKaiB → fsKaiB transition is nearly three times smaller than that for the reverse transition. Simulations and native-state hydrogen-deuterium exchange NMR experiments suggest that fold switching can involve both subglobally and near-globally unfolded intermediates. The simulations predict that the transition state for fold switching coincides with isomerization of conserved prolines in the most rapidly exchanging region, and we confirm experimentally that proline isomerization is a rate-limiting step for fold switching. We explore the implications of our results for temperature compensation, a hallmark of circadian clocks, through a kinetic model.
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4
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Monteiro da Silva G, Cui JY, Dalgarno DC, Lisi GP, Rubenstein BM. High-throughput prediction of protein conformational distributions with subsampled AlphaFold2. Nat Commun 2024; 15:2464. [PMID: 38538622 PMCID: PMC10973385 DOI: 10.1038/s41467-024-46715-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 02/28/2024] [Indexed: 04/12/2024] Open
Abstract
This paper presents an innovative approach for predicting the relative populations of protein conformations using AlphaFold 2, an AI-powered method that has revolutionized biology by enabling the accurate prediction of protein structures. While AlphaFold 2 has shown exceptional accuracy and speed, it is designed to predict proteins' ground state conformations and is limited in its ability to predict conformational landscapes. Here, we demonstrate how AlphaFold 2 can directly predict the relative populations of different protein conformations by subsampling multiple sequence alignments. We tested our method against nuclear magnetic resonance experiments on two proteins with drastically different amounts of available sequence data, Abl1 kinase and the granulocyte-macrophage colony-stimulating factor, and predicted changes in their relative state populations with more than 80% accuracy. Our subsampling approach worked best when used to qualitatively predict the effects of mutations or evolution on the conformational landscape and well-populated states of proteins. It thus offers a fast and cost-effective way to predict the relative populations of protein conformations at even single-point mutation resolution, making it a useful tool for pharmacology, analysis of experimental results, and predicting evolution.
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Affiliation(s)
| | - Jennifer Y Cui
- Brown University Department of Molecular and Cell Biology and Biochemistry, Providence, RI, USA
| | | | - George P Lisi
- Brown University Department of Molecular and Cell Biology and Biochemistry, Providence, RI, USA
- Brown University Department of Chemistry, Providence, RI, USA
| | - Brenda M Rubenstein
- Brown University Department of Molecular and Cell Biology and Biochemistry, Providence, RI, USA.
- Brown University Department of Chemistry, Providence, RI, USA.
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5
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Montrose K, Lac DT, Burnetti AJ, Tong K, Bozdag GO, Hukkanen M, Ratcliff WC, Saarikangas J. Proteostatic tuning underpins the evolution of novel multicellular traits. SCIENCE ADVANCES 2024; 10:eadn2706. [PMID: 38457507 PMCID: PMC10923498 DOI: 10.1126/sciadv.adn2706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/06/2024] [Indexed: 03/10/2024]
Abstract
The evolution of multicellularity paved the way for the origin of complex life on Earth, but little is known about the mechanistic basis of early multicellular evolution. Here, we examine the molecular basis of multicellular adaptation in the multicellularity long-term evolution experiment (MuLTEE). We demonstrate that cellular elongation, a key adaptation underpinning increased biophysical toughness and organismal size, is convergently driven by down-regulation of the chaperone Hsp90. Mechanistically, Hsp90-mediated morphogenesis operates by destabilizing the cyclin-dependent kinase Cdc28, resulting in delayed mitosis and prolonged polarized growth. Reinstatement of Hsp90 or Cdc28 expression resulted in shortened cells that formed smaller groups with reduced multicellular fitness. Together, our results show how ancient protein folding systems can be tuned to drive rapid evolution at a new level of biological individuality by revealing novel developmental phenotypes.
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Affiliation(s)
- Kristopher Montrose
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Dung T. Lac
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Anthony J. Burnetti
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kai Tong
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Interdisciplinary Graduate Program in Quantitative Biosciences (QBioS), Georgia Institute of Technology, Atlanta, GA, USA
| | - G. Ozan Bozdag
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mikaela Hukkanen
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - William C. Ratcliff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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6
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Montrose K, Lac DT, Burnetti AJ, Tong K, Ozan Bozdag G, Hukkanen M, Ratcliff WC, Saarikangas J. Proteostatic tuning underpins the evolution of novel multicellular traits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.31.543183. [PMID: 37333256 PMCID: PMC10274739 DOI: 10.1101/2023.05.31.543183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
The evolution of multicellularity paved the way for the origin of complex life on Earth, but little is known about the mechanistic basis of early multicellular evolution. Here, we examine the molecular basis of multicellular adaptation in the Multicellularity Long Term Evolution Experiment (MuLTEE). We demonstrate that cellular elongation, a key adaptation underpinning increased biophysical toughness and organismal size, is convergently driven by downregulation of the chaperone Hsp90. Mechanistically, Hsp90-mediated morphogenesis operates by destabilizing the cyclin-dependent kinase Cdc28, resulting in delayed mitosis and prolonged polarized growth. Reinstatement of Hsp90 or Cdc28 expression resulted in shortened cells that formed smaller groups with reduced multicellular fitness. Together, our results show how ancient protein folding systems can be tuned to drive rapid evolution at a new level of biological individuality by revealing novel developmental phenotypes.
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Affiliation(s)
- Kristopher Montrose
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki
- Faculty of Biological and Environmental Sciences, University of Helsinki
| | - Dung T. Lac
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Anthony J. Burnetti
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kai Tong
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki
- Faculty of Biological and Environmental Sciences, University of Helsinki
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Interdisciplinary Graduate Program in Quantitative Biosciences (QBioS)
| | - G. Ozan Bozdag
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Mikaela Hukkanen
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki
- Faculty of Biological and Environmental Sciences, University of Helsinki
| | - William C. Ratcliff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Juha Saarikangas
- Helsinki Institute of Life Science, HiLIFE, University of Helsinki
- Faculty of Biological and Environmental Sciences, University of Helsinki
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7
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da Silva GM, Cui JY, Dalgarno DC, Lisi GP, Rubenstein BM. Predicting Relative Populations of Protein Conformations without a Physics Engine Using AlphaFold 2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550545. [PMID: 37546747 PMCID: PMC10402055 DOI: 10.1101/2023.07.25.550545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
This paper presents a novel approach for predicting the relative populations of protein conformations using AlphaFold 2, an AI-powered method that has revolutionized biology by enabling the accurate prediction of protein structures. While AlphaFold 2 has shown exceptional accuracy and speed, it is designed to predict proteins' ground state conformations and is limited in its ability to predict conformational landscapes. Here, we demonstrate how AlphaFold 2 can directly predict the relative populations of different protein conformations by subsampling multiple sequence alignments. We tested our method against NMR experiments on two proteins with drastically different amounts of available sequence data, Abl1 kinase and the granulocyte-macrophage colony-stimulating factor, and predicted changes in their relative state populations with more than 80% accuracy. Our subsampling approach worked best when used to qualitatively predict the effects of mutations or evolution on the conformational landscape and well-populated states of proteins. It thus offers a fast and cost-effective way to predict the relative populations of protein conformations at even single-point mutation resolution, making it a useful tool for pharmacology, NMR analysis, and evolution.
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Affiliation(s)
- Gabriel Monteiro da Silva
- Brown University Department of Molecular Biology, Cell Biology, and Biochemistry, Providence, RI, USA
| | - Jennifer Y Cui
- Brown University Department of Molecular Biology, Cell Biology, and Biochemistry, Providence, RI, USA
| | | | - George P Lisi
- Brown University Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University Department of Chemistry, Providence, RI, USA
| | - Brenda M Rubenstein
- Brown University Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University Department of Chemistry, Providence, RI, USA
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8
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Chakravarty D, Schafer JW, Chen EA, Thole JR, Porter LL. AlphaFold2 has more to learn about protein energy landscapes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571380. [PMID: 38168383 PMCID: PMC10760193 DOI: 10.1101/2023.12.12.571380] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Recent work suggests that AlphaFold2 (AF2)-a deep learning-based model that can accurately infer protein structure from sequence-may discern important features of folded protein energy landscapes, defined by the diversity and frequency of different conformations in the folded state. Here, we test the limits of its predictive power on fold-switching proteins, which assume two structures with regions of distinct secondary and/or tertiary structure. Using several implementations of AF2, including two published enhanced sampling approaches, we generated >280,000 models of 93 fold-switching proteins whose experimentally determined conformations were likely in AF2's training set. Combining all models, AF2 predicted fold switching with a modest success rate of ~25%, indicating that it does not readily sample both experimentally characterized conformations of most fold switchers. Further, AF2's confidence metrics selected against models consistent with experimentally determined fold-switching conformations in favor of inconsistent models. Accordingly, these confidence metrics-though suggested to evaluate protein energetics reliably-did not discriminate between low and high energy states of fold-switching proteins. We then evaluated AF2's performance on seven fold-switching proteins outside of its training set, generating >159,000 models in total. Fold switching was accurately predicted in one of seven targets with moderate confidence. Further, AF2 demonstrated no ability to predict alternative conformations of two newly discovered targets without homologs in the set of 93 fold switchers. These results indicate that AF2 has more to learn about the underlying energetics of protein ensembles and highlight the need for further developments of methods that readily predict multiple protein conformations.
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Affiliation(s)
- Devlina Chakravarty
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - Joseph W. Schafer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - Ethan A. Chen
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - Joseph R. Thole
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892
| | - Lauren L. Porter
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892
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9
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Russell PPS, Rickard MM, Boob M, Gruebele M, Pogorelov TV. In silico protein dynamics in the human cytoplasm: Partial folding, misfolding, fold switching, and non-native interactions. Protein Sci 2023; 32:e4790. [PMID: 37774143 PMCID: PMC10578126 DOI: 10.1002/pro.4790] [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: 05/23/2023] [Revised: 08/10/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
We examine the influence of cellular interactions in all-atom models of a section of the Homo sapiens cytoplasm on the early folding events of the three-helix bundle protein B (PB). While genetically engineered PB is known to fold in dilute water box simulations in three microseconds, the three initially unfolded PB copies in our two cytoplasm models using a similar force field did not reach the native state during 30-microsecond simulations. We did however capture the formation of all three helices in a compact native-like topology. Folding in vivo is delayed because intramolecular contact formation within PB is in direct competition with intermolecular contacts between PB and surrounding macromolecules. In extreme cases, intermolecular beta-sheets are formed. Interactions with other macromolecules are also observed to promote structure formation, for example when a PB helix in our simulations is shielded from solvent by macromolecular crowding. Sticking and crowding in our models initiate sampling of helix/sheet structural plasticity of PB. Relatedly, in past in vitro experiments, similar GA domains were shown to switch between two different folds. Finally, we also observed that stickiness between PB and the cellular environment can be modulated in our simulations through the reduction in protein hydrophobicity when we reversed PB back to the wild-type sequence. This study demonstrates that even fast-folding proteins can get stuck in non-native states in the cell, making them useful models for protein-chaperone interactions and early stages of aggregate formation relevant to cellular disease.
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Affiliation(s)
| | - Meredith M. Rickard
- Department of ChemistryUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Mayank Boob
- Center for Biophysics and Quantitative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Martin Gruebele
- Department of ChemistryUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Center for Biophysics and Quantitative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- Department of PhysicsUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Taras V. Pogorelov
- Department of ChemistryUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Center for Biophysics and Quantitative BiologyUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- Beckman Institute for Advanced Science and TechnologyUniversity of Illinois at Urbana‐ChampaignUrbanaIllinoisUSA
- National Center for Supercomputing ApplicationsUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
- School of Chemical SciencesUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
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10
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Parui S, Brini E, Dill KA. Computing Free Energies of Fold-Switching Proteins Using MELD x MD. J Chem Theory Comput 2023; 19:6839-6847. [PMID: 37725050 DOI: 10.1021/acs.jctc.3c00679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Some proteins are conformational switches, able to transition between relatively different conformations. To understand what drives them requires computing the free-energy difference ΔGAB between their stable states, A and B. Molecular dynamics (MD) simulations alone are often slow because they require a reaction coordinate and must sample many transitions in between. Here, we show that modeling employing limited data (MELD) x MD on known endstates A and B is accurate and efficient because it does not require passing over barriers or knowing reaction coordinates. We validate this method on two problems: (1) it gives correct relative populations of α and β conformers for small designed chameleon sequences of protein G; and (2) it correctly predicts the conformations of the C-terminal domain (CTD) of RfaH. Free-energy methods like MELD x MD can often resolve structures that confuse machine-learning (ML) methods.
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Affiliation(s)
- Sridip Parui
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
| | - Emiliano Brini
- School of Chemistry and Materials Science, 85 Lomb Memorial Drive, Rochester, New York 14623, United States
| | - Ken A Dill
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
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11
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Kosenko M, Onkhonova G, Susloparov I, Ryzhikov A. SARS-CoV-2 proteins structural studies using synchrotron radiation. Biophys Rev 2023; 15:1185-1194. [PMID: 37974992 PMCID: PMC10643813 DOI: 10.1007/s12551-023-01153-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/20/2023] [Indexed: 11/19/2023] Open
Abstract
In the process of the development of structural biology, both the size and the complexity of the determined macromolecular structures have grown significantly. As a result, the range of application areas for the results of structural studies of biological macromolecules has expanded. Significant progress in the development of structural biology methods has been largely achieved through the use of synchrotron radiation. Modern sources of synchrotron radiation allow to conduct high-performance structural studies with high temporal and spatial resolution. Thus, modern techniques make it possible to obtain not only static structures, but also to study dynamic processes, which play a key role in understanding biological mechanisms. One of the key directions in the development of structural research is the drug design based on the structures of biomolecules. Synchrotron radiation offers insights into the three-dimensional time-resolved structure of individual viral proteins and their complexes at atomic resolution. The rapid and accurate determination of protein structures is crucial for understanding viral pathogenicity and designing targeted therapeutics. Through the application of experimental techniques, including X-ray crystallography and small-angle X-ray scattering (SAXS), it is possible to elucidate the structural details of SARS-CoV-2 virion containing 4 structural, 16 nonstructural proteins (nsp), and several accessory proteins. The most studied potential targets for vaccines and drugs are the structural spike (S) protein, which is responsible for entering the host cell, as well as nonstructural proteins essential for replication and transcription, such as main protease (Mpro), papain-like protease (PLpro), and RNA-dependent RNA polymerase (RdRp). This article provides a brief overview of structural analysis techniques, with focus on synchrotron radiation-based methods applied to the analysis of SARS-CoV-2 proteins.
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Affiliation(s)
- Maksim Kosenko
- Federal Budgetary Research Institution State Research Center of Virology and Biotechnology “Vector” Rospotrebnadzor, Koltsovo, 630559 Russia
| | - Galina Onkhonova
- Federal Budgetary Research Institution State Research Center of Virology and Biotechnology “Vector” Rospotrebnadzor, Koltsovo, 630559 Russia
| | - Ivan Susloparov
- Federal Budgetary Research Institution State Research Center of Virology and Biotechnology “Vector” Rospotrebnadzor, Koltsovo, 630559 Russia
| | - Alexander Ryzhikov
- Federal Budgetary Research Institution State Research Center of Virology and Biotechnology “Vector” Rospotrebnadzor, Koltsovo, 630559 Russia
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12
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Bazmi S, Seifi B, Wallin S. Simulations of a protein fold switch reveal crowding-induced population shifts driven by disordered regions. Commun Chem 2023; 6:191. [PMID: 37689829 PMCID: PMC10492864 DOI: 10.1038/s42004-023-00995-2] [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: 04/04/2023] [Accepted: 08/24/2023] [Indexed: 09/11/2023] Open
Abstract
Macromolecular crowding effects on globular proteins, which usually adopt a single stable fold, have been widely studied. However, little is known about crowding effects on fold-switching proteins, which reversibly switch between distinct folds. Here we study the mutationally driven switch between the folds of GA and GB, the two 56-amino acid binding domains of protein G, using a structure-based dual-basin model. We show that, in the absence of crowders, the fold populations PA and PB can be controlled by the strengths of contacts in the two folds, κA and κB. A population balance, PA ≈ PB, is obtained for κB/κA = 0.92. The resulting model protein is subject to crowding at different packing fractions, ϕc. We find that crowding increases the GB population and reduces the GA population, reaching PB/PA ≈ 4 at ϕc = 0.44. We analyze the ϕc-dependence of the crowding-induced GA-to-GB switch using scaled particle theory, which provides a qualitative, but not quantitative, fit of our data, suggesting effects beyond a spherical description of the folds. We show that the terminal regions of the protein chain, which are intrinsically disordered only in GA, play a dominant role in the response of the fold switch to crowding effects.
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Affiliation(s)
- Saman Bazmi
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada
| | - Bahman Seifi
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada
| | - Stefan Wallin
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, A1B 3X7, Canada.
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13
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Schafer JW, Porter LL. Evolutionary selection of proteins with two folds. Nat Commun 2023; 14:5478. [PMID: 37673981 PMCID: PMC10482954 DOI: 10.1038/s41467-023-41237-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023] Open
Abstract
Although most globular proteins fold into a single stable structure, an increasing number have been shown to remodel their secondary and tertiary structures in response to cellular stimuli. State-of-the-art algorithms predict that these fold-switching proteins adopt only one stable structure, missing their functionally critical alternative folds. Why these algorithms predict a single fold is unclear, but all of them infer protein structure from coevolved amino acid pairs. Here, we hypothesize that coevolutionary signatures are being missed. Suspecting that single-fold variants could be masking these signatures, we developed an approach, called Alternative Contact Enhancement (ACE), to search both highly diverse protein superfamilies-composed of single-fold and fold-switching variants-and protein subfamilies with more fold-switching variants. ACE successfully revealed coevolution of amino acid pairs uniquely corresponding to both conformations of 56/56 fold-switching proteins from distinct families. Then, we used ACE-derived contacts to (1) predict two experimentally consistent conformations of a candidate protein with unsolved structure and (2) develop a blind prediction pipeline for fold-switching proteins. The discovery of widespread dual-fold coevolution indicates that fold-switching sequences have been preserved by natural selection, implying that their functionalities provide evolutionary advantage and paving the way for predictions of diverse protein structures from single sequences.
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Affiliation(s)
- Joseph W Schafer
- National Library of Medicine, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Lauren L Porter
- National Library of Medicine, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, 20894, USA.
- National Heart, Lung, and Blood Institute, Biochemistry and Biophysics Center, National Institutes of Health, Bethesda, MD, 20892, USA.
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14
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Porter LL. Fluid protein fold space and its implications. Bioessays 2023; 45:e2300057. [PMID: 37431685 PMCID: PMC10529699 DOI: 10.1002/bies.202300057] [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: 03/30/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023]
Abstract
Fold-switching proteins, which remodel their secondary and tertiary structures in response to cellular stimuli, suggest a new view of protein fold space. For decades, experimental evidence has indicated that protein fold space is discrete: dissimilar folds are encoded by dissimilar amino acid sequences. Challenging this assumption, fold-switching proteins interconnect discrete groups of dissimilar protein folds, making protein fold space fluid. Three recent observations support the concept of fluid fold space: (1) some amino acid sequences interconvert between folds with distinct secondary structures, (2) some naturally occurring sequences have switched folds by stepwise mutation, and (3) fold switching is evolutionarily selected and likely confers advantage. These observations indicate that minor amino acid sequence modifications can transform protein structure and function. Consequently, proteomic structural and functional diversity may be expanded by alternative splicing, small nucleotide polymorphisms, post-translational modifications, and modified translation rates.
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Affiliation(s)
- Lauren L. Porter
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD
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15
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Praetorius F, Leung PJY, Tessmer MH, Broerman A, Demakis C, Dishman AF, Pillai A, Idris A, Juergens D, Dauparas J, Li X, Levine PM, Lamb M, Ballard RK, Gerben SR, Nguyen H, Kang A, Sankaran B, Bera AK, Volkman BF, Nivala J, Stoll S, Baker D. Design of stimulus-responsive two-state hinge proteins. Science 2023; 381:754-760. [PMID: 37590357 PMCID: PMC10697137 DOI: 10.1126/science.adg7731] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/11/2023] [Indexed: 08/19/2023]
Abstract
In nature, proteins that switch between two conformations in response to environmental stimuli structurally transduce biochemical information in a manner analogous to how transistors control information flow in computing devices. Designing proteins with two distinct but fully structured conformations is a challenge for protein design as it requires sculpting an energy landscape with two distinct minima. Here we describe the design of "hinge" proteins that populate one designed state in the absence of ligand and a second designed state in the presence of ligand. X-ray crystallography, electron microscopy, double electron-electron resonance spectroscopy, and binding measurements demonstrate that despite the significant structural differences the two states are designed with atomic level accuracy and that the conformational and binding equilibria are closely coupled.
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Affiliation(s)
- Florian Praetorius
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Philip J. Y. Leung
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Graduate Program in Molecular Engineering, University of Washington, Seattle, WA, USA
| | - Maxx H. Tessmer
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Adam Broerman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA
| | - Cullen Demakis
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Graduate Program in Biological Physics, Structure, and Design, University of Washington, Seattle, Washington, USA
| | - Acacia F. Dishman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
- Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Arvind Pillai
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Abbas Idris
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - David Juergens
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Graduate Program in Molecular Engineering, University of Washington, Seattle, WA, USA
| | - Justas Dauparas
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Xinting Li
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Paul M. Levine
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Mila Lamb
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Ryanne K. Ballard
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Stacey R. Gerben
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Hannah Nguyen
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Asim K. Bera
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jeff Nivala
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, WA, USA
- Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA, USA
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA,USA
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16
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Dishman AF, Volkman BF. Metamorphic protein folding as evolutionary adaptation. Trends Biochem Sci 2023; 48:665-672. [PMID: 37270322 PMCID: PMC10526677 DOI: 10.1016/j.tibs.2023.05.001] [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: 02/03/2023] [Revised: 04/12/2023] [Accepted: 05/04/2023] [Indexed: 06/05/2023]
Abstract
Metamorphic proteins switch reversibly between multiple distinct, stable structures, often with different functions. It was previously hypothesized that metamorphic proteins arose as intermediates in the evolution of a new fold - rare and transient exceptions to the 'one sequence, one fold' paradigm. However, as described herein, mounting evidence suggests that metamorphic folding is an adaptive feature, preserved and optimized over evolutionary time as exemplified by the NusG family and the chemokine XCL1. Analysis of extant protein families and resurrected protein ancestors demonstrates that large regions of sequence space are compatible with metamorphic folding. As a category that enhances biological fitness, metamorphic proteins are likely to employ fold switching to perform important biological functions and may be more common than previously thought.
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Affiliation(s)
- Acacia F Dishman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Program in Chemical Biology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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17
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Kulkarni P, Salgia R, Rangarajan G. Intrinsically disordered proteins and conformational noise: The hypothesis a decade later. iScience 2023; 26:107109. [PMID: 37408690 PMCID: PMC10319216 DOI: 10.1016/j.isci.2023.107109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023] Open
Abstract
Phenotypic plasticity is the ability of individual genotypes to produce different phenotypes in response to environmental perturbations. We previously postulated how conformational noise emanating from conformational dynamics of intrinsically disordered proteins (IDPs) which is distinct from transcriptional noise, can contribute to phenotypic switching by rewiring the cellular protein interaction network. Since most transcription factors are IDPs, we posited that conformational noise is an integral component of transcriptional noise implying that IDPs may amplify total noise in the system either stochastically or in response to environmental changes. Here, we review progress in elucidating the details of the hypothesis. We highlight empirical evidence supporting the hypothesis, discuss conceptual advances that underscore its fundamental importance and implications, and identify areas for future investigations.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
- Department of Systems Biology, City of Hope National Medical Center, Duarte, CA, USA
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
- Center for Neuroscience, Indian Institute of Science, Bangalore 560012, India
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18
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Conev A, Rigo MM, Devaurs D, Fonseca AF, Kalavadwala H, de Freitas MV, Clementi C, Zanatta G, Antunes DA, Kavraki LE. EnGens: a computational framework for generation and analysis of representative protein conformational ensembles. Brief Bioinform 2023; 24:bbad242. [PMID: 37418278 PMCID: PMC10359083 DOI: 10.1093/bib/bbad242] [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: 03/11/2023] [Revised: 05/23/2023] [Accepted: 06/10/2023] [Indexed: 07/08/2023] Open
Abstract
Proteins are dynamic macromolecules that perform vital functions in cells. A protein structure determines its function, but this structure is not static, as proteins change their conformation to achieve various functions. Understanding the conformational landscapes of proteins is essential to understand their mechanism of action. Sets of carefully chosen conformations can summarize such complex landscapes and provide better insights into protein function than single conformations. We refer to these sets as representative conformational ensembles. Recent advances in computational methods have led to an increase in the number of available structural datasets spanning conformational landscapes. However, extracting representative conformational ensembles from such datasets is not an easy task and many methods have been developed to tackle it. Our new approach, EnGens (short for ensemble generation), collects these methods into a unified framework for generating and analyzing representative protein conformational ensembles. In this work, we: (1) provide an overview of existing methods and tools for representative protein structural ensemble generation and analysis; (2) unify existing approaches in an open-source Python package, and a portable Docker image, providing interactive visualizations within a Jupyter Notebook pipeline; (3) test our pipeline on a few canonical examples from the literature. Representative ensembles produced by EnGens can be used for many downstream tasks such as protein-ligand ensemble docking, Markov state modeling of protein dynamics and analysis of the effect of single-point mutations.
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Affiliation(s)
- Anja Conev
- Department of Computer Science, Rice University, Houston 77005, TX, USA
| | | | - Didier Devaurs
- MRC Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | | | - Hussain Kalavadwala
- Department of Biology and Biochemistry, University of Houston, Houston 77004, TX, USA
| | | | - Cecilia Clementi
- Department of Physics, Freie Universität Berlin, Berlin 14195, Germany
| | - Geancarlo Zanatta
- Department of Biophysics, Institute of Biosciences, Federal University of Rio Grande do Sul, Porto Alegre 91501-970, Brazil
| | - Dinler Amaral Antunes
- Department of Biology and Biochemistry, University of Houston, Houston 77004, TX, USA
| | - Lydia E Kavraki
- Department of Computer Science, Rice University, Houston 77005, TX, USA
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19
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Zhang N, Guan W, Cui S, Ai N. Crowded environments tune the fold-switching in metamorphic proteins. Commun Chem 2023; 6:117. [PMID: 37291449 PMCID: PMC10250422 DOI: 10.1038/s42004-023-00909-2] [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: 02/21/2023] [Accepted: 05/22/2023] [Indexed: 06/10/2023] Open
Abstract
Metamorphic proteins such as circadian clock protein KaiB and human chemokine XCL1 play vital roles in regulating biological processes, including gene expression, circadian clock and innate immune responses, and perform distinct functions in living cell by switching different structures in response to cellular environment stimuli. However, it is unclear how complex and crowded intracellular environments affect conformational rearrangement of metamorphic proteins. Here, the kinetics and thermodynamics of two well-characterized metamorphic proteins, circadian clock protein KaiB and human chemokine XCL1, were quantified in physiologically relevant environments by using NMR spectroscopy, indicating that crowded agents shift equilibrium towards the inactive form (ground-state KaiB and Ltn10-like state XCL1) without disturbing the corresponding structures, and crowded agents have predominantly impact on the exchange rate of XCL1 that switches folds on timescales of seconds, but have slightly impact on the exchange rate of KaiB that switches folds on timescales of hours. Our data shed light on how metamorphic proteins can respond immediately to the changed crowded intracellular conditions that induced by environmental cues and then execute different functions in living cell, and it also enhances our understanding of how environments enrich the sequence-structure-function paradigm.
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Affiliation(s)
- Ning Zhang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
- Shandong Energy Institute, Qingdao, 266101, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China.
| | - Wenyan Guan
- Materials and Biomaterials Science and Engineering, University of California, Merced, CA, 95343, USA
| | - Shouqi Cui
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Nana Ai
- Materials and Biomaterials Science and Engineering, University of California, Merced, CA, 95343, USA
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20
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Conev A, Rigo MM, Devaurs D, Fonseca AF, Kalavadwala H, de Freitas MV, Clementi C, Zanatta G, Antunes DA, Kavraki L. EnGens: a computational framework for generation and analysis of representative protein conformational ensembles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538094. [PMID: 37163076 PMCID: PMC10168271 DOI: 10.1101/2023.04.24.538094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Proteins are dynamic macromolecules that perform vital functions in cells. A protein structure determines its function, but this structure is not static, as proteins change their conformation to achieve various functions. Understanding the conformational landscapes of proteins is essential to understand their mechanism of action. Sets of carefully chosen conformations can summarize such complex landscapes and provide better insights into protein function than single conformations. We refer to these sets as representative conformational ensembles. Recent advances in computational methods have led to an increase in number of available structural datasets spanning conformational landscapes. However, extracting representative conformational ensembles from such datasets is not an easy task and many methods have been developed to tackle it. Our new approach, EnGens (short for ensemble generation), collects these methods into a unified framework for generating and analyzing protein conformational ensembles. In this work we: (1) provide an overview of existing methods and tools for protein structural ensemble generation and analysis; (2) unify existing approaches in an open-source Python package, and a portable Docker image, providing interactive visualizations within a Jupyter Notebook pipeline; (3) test our pipeline on a few canonical examples found in the literature. Representative ensembles produced by EnGens can be used for many downstream tasks such as protein-ligand ensemble docking, Markov state modeling of protein dynamics and analysis of the effect of single-point mutations.
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21
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Liu S, Chen H, Yin Y, Lu D, Gao G, Li J, Bai XC, Zhang X. Inhibition of FAM46/TENT5 activity by BCCIPα adopting a unique fold. SCIENCE ADVANCES 2023; 9:eadf5583. [PMID: 37018411 PMCID: PMC10075960 DOI: 10.1126/sciadv.adf5583] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/07/2023] [Indexed: 06/19/2023]
Abstract
The FAM46 (also known as TENT5) proteins are noncanonical poly(A) polymerases (PAPs) implicated in regulating RNA stability. The regulatory mechanisms of FAM46 are poorly understood. Here, we report that the nuclear protein BCCIPα, but not the alternatively spliced isoform BCCIPβ, binds FAM46 and inhibits their PAP activity. Unexpectedly, our structures of the FAM46A/BCCIPα and FAM46C/BCCIPα complexes show that, despite sharing most of the sequence and differing only at the C-terminal portion, BCCIPα adopts a unique structure completely different from BCCIPβ. The distinct C-terminal segment of BCCIPα supports the adoption of the unique fold but does not directly interact with FAM46. The β sheets in BCCIPα and FAM46 pack side by side to form an extended β sheet. A helix-loop-helix segment in BCCIPα inserts into the active site cleft of FAM46, thereby inhibiting the PAP activity. Our results together show that the unique fold of BCCIPα underlies its interaction with and functional regulation of FAM46.
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Affiliation(s)
- Shun Liu
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hua Chen
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yan Yin
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Defen Lu
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guoming Gao
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jie Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xuewu Zhang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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22
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Chakravarty D, Schafer JW, Porter LL. Distinguishing features of fold-switching proteins. Protein Sci 2023; 32:e4596. [PMID: 36782353 PMCID: PMC9951197 DOI: 10.1002/pro.4596] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/30/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
Though many folded proteins assume one stable structure that performs one function, a small-but-increasing number remodel their secondary and tertiary structures and change their functions in response to cellular stimuli. These fold-switching proteins regulate biological processes and are associated with autoimmune dysfunction, severe acute respiratory syndrome coronavirus-2 infection, and more. Despite their biological importance, it is difficult to computationally predict fold switching. With the aim of advancing computational prediction and experimental characterization of fold switchers, this review discusses several features that distinguish fold-switching proteins from their single-fold and intrinsically disordered counterparts. First, the isolated structures of fold switchers are less stable and more heterogeneous than single folders but more stable and less heterogeneous than intrinsically disordered proteins (IDPs). Second, the sequences of single fold, fold switching, and intrinsically disordered proteins can evolve at distinct rates. Third, proteins from these three classes are best predicted using different computational techniques. Finally, late-breaking results suggest that single folders, fold switchers, and IDPs have distinct patterns of residue-residue coevolution. The review closes by discussing high-throughput and medium-throughput experimental approaches that might be used to identify new fold-switching proteins.
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Affiliation(s)
- Devlina Chakravarty
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaMarylandUSA
| | - Joseph W. Schafer
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaMarylandUSA
| | - Lauren L. Porter
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of HealthBethesdaMarylandUSA
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of HealthBethesdaMarylandUSA
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23
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Schafer JW, Porter LL. Evolutionary selection of proteins with two folds. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524637. [PMID: 36789442 PMCID: PMC9928049 DOI: 10.1101/2023.01.18.524637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Although most globular proteins fold into a single stable structure 1 , an increasing number have been shown to remodel their secondary and tertiary structures in response to cellular stimuli 2 . State-of-the-art algorithms 3-5 predict that these fold-switching proteins assume only one stable structure 6,7 , missing their functionally critical alternative folds. Why these algorithms predict a single fold is unclear, but all of them infer protein structure from coevolved amino acid pairs. Here, we hypothesize that coevolutionary signatures are being missed. Suspecting that over-represented single-fold sequences may be masking these signatures, we developed an approach to search both highly diverse protein superfamilies-composed of single-fold and fold-switching variants-and protein subfamilies with more fold-switching variants. This approach successfully revealed coevolution of amino acid pairs uniquely corresponding to both conformations of 56/58 fold-switching proteins from distinct families. Then, using a set of coevolved amino acid pairs predicted by our approach, we successfully biased AlphaFold2 5 to predict two experimentally consistent conformations of a candidate protein with unsolved structure. The discovery of widespread dual-fold coevolution indicates that fold-switching sequences have been preserved by natural selection, implying that their functionalities provide evolutionary advantage and paving the way for predictions of diverse protein structures from single sequences.
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Affiliation(s)
- Joseph W. Schafer
- National Library of Medicine, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20894, USA
| | - Lauren L. Porter
- National Library of Medicine, National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD 20894, USA
- National Heart, Lung, and Blood Institute, Biochemistry and Biophysics Center, National Institutes of Health, Bethesda, MD 20892, USA
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24
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Soni R, Krishna AM, More SH, Sharma A. Reversible Modulation of Aptamer-Ligand Binding in RNA Light-Up Aptamers Containing G-Quadruplex Using Chemical Stimuli. Chembiochem 2023; 24:e202200574. [PMID: 36352557 DOI: 10.1002/cbic.202200574] [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: 10/04/2022] [Revised: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Regulating a system in equilibrium transiently to out-of-equilibrium by using certain stimuli is the strategy used by natural biomolecules to function. Herein, we showed that the interaction of synthetic RNA aptamers, having a G-quadruplex core structure, with their corresponding ligands could be regulated from their equilibrium state to non-equilibrium state in a reversible manner using simple chemical stimuli (Ag+ and cysteine). The approach would be useful for designing aptamer regulators that work in a dynamic nucleic acid network, where a strict control on aptamer-ligand interaction is needed. In addition, to the best of our knowledge, this is the first report which shows that RNA G-quadruplexes can be disrupted by the addition of silver ions. This would be useful not only in designing RNA-based sensors or regulators but would also be useful for understanding the role of metal ions in RNA folding and catalysis.
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Affiliation(s)
- Rashi Soni
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507, Andhra Pradesh, India
| | - A Murali Krishna
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507, Andhra Pradesh, India
| | - Shahaji H More
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507, Andhra Pradesh, India
| | - Ashwani Sharma
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507, Andhra Pradesh, India.,Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, 517507, Andhra Pradesh, India
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25
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Artsimovitch I, Ramírez-Sarmiento CA. Metamorphic proteins under a computational microscope: Lessons from a fold-switching RfaH protein. Comput Struct Biotechnol J 2022; 20:5824-5837. [PMID: 36382197 PMCID: PMC9630627 DOI: 10.1016/j.csbj.2022.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/18/2022] [Accepted: 10/18/2022] [Indexed: 11/28/2022] Open
Abstract
Metamorphic proteins constitute unexpected paradigms of the protein folding problem, as their sequences encode two alternative folds, which reversibly interconvert within biologically relevant timescales to trigger different cellular responses. Once considered a rare aberration, metamorphism may be common among proteins that must respond to rapidly changing environments, exemplified by NusG-like proteins, the only transcription factors present in every domain of life. RfaH, a specialized paralog of bacterial NusG, undergoes an all-α to all-β domain switch to activate expression of virulence and conjugation genes in many animal and plant pathogens and is the quintessential example of a metamorphic protein. The dramatic nature of RfaH structural transformation and the richness of its evolutionary history makes for an excellent model for studying how metamorphic proteins switch folds. Here, we summarize the structural and functional evidence that sparked the discovery of RfaH as a metamorphic protein, the experimental and computational approaches that enabled the description of the molecular mechanism and refolding pathways of its structural interconversion, and the ongoing efforts to find signatures and general properties to ultimately describe the protein metamorphome.
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Affiliation(s)
- Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - César A. Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID, Millennium Science Initiative Program, Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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26
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Harman JL, Reardon PN, Costello SM, Warren GD, Phillips SR, Connor PJ, Marqusee S, Harms MJ. Evolution avoids a pathological stabilizing interaction in the immune protein S100A9. Proc Natl Acad Sci U S A 2022; 119:e2208029119. [PMID: 36194634 PMCID: PMC9565474 DOI: 10.1073/pnas.2208029119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/07/2022] [Indexed: 01/03/2023] Open
Abstract
Stability constrains evolution. While much is known about constraints on destabilizing mutations, less is known about the constraints on stabilizing mutations. We recently identified a mutation in the innate immune protein S100A9 that provides insight into such constraints. When introduced into human S100A9, M63F simultaneously increases the stability of the protein and disrupts its natural ability to activate Toll-like receptor 4. Using chemical denaturation, we found that M63F stabilizes a calcium-bound conformation of hS100A9. We then used NMR to solve the structure of the mutant protein, revealing that the mutation distorts the hydrophobic binding surface of hS100A9, explaining its deleterious effect on function. Hydrogen-deuterium exchange (HDX) experiments revealed stabilization of the region around M63F in the structure, notably Phe37. In the structure of the M63F mutant, the Phe37 and Phe63 sidechains are in contact, plausibly forming an edge-face π-stack. Mutating Phe37 to Leu abolished the stabilizing effect of M63F as probed by both chemical denaturation and HDX. It also restored the biological activity of S100A9 disrupted by M63F. These findings reveal that Phe63 creates a molecular staple with Phe37 that stabilizes a nonfunctional conformation of the protein, thus disrupting function. Using a bioinformatic analysis, we found that S100A9 proteins from different organisms rarely have Phe at both positions 37 and 63, suggesting that avoiding a pathological stabilizing interaction indeed constrains S100A9 evolution. This work highlights an important evolutionary constraint on stabilizing mutations, namely, that they must avoid inappropriately stabilizing nonfunctional protein conformations.
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Affiliation(s)
- Joseph L Harman
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Patrick N Reardon
- College of Science, NMR Facility, Oregon State University, Corvallis, OR 97331
| | - Shawn M Costello
- Biophysics Graduate Program, University of California, Berkeley, Berkeley, CA 94720
| | - Gus D Warren
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Sophia R Phillips
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Patrick J Connor
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Susan Marqusee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
| | - Michael J Harms
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
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27
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Many dissimilar NusG protein domains switch between α-helix and β-sheet folds. Nat Commun 2022; 13:3802. [PMID: 35778397 PMCID: PMC9247905 DOI: 10.1038/s41467-022-31532-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/17/2022] [Indexed: 11/16/2022] Open
Abstract
Folded proteins are assumed to be built upon fixed scaffolds of secondary structure, α-helices and β-sheets. Experimentally determined structures of >58,000 non-redundant proteins support this assumption, though it has recently been challenged by ~100 fold-switching proteins. Though ostensibly rare, these proteins raise the question of how many uncharacterized proteins have shapeshifting–rather than fixed–secondary structures. Here, we use a comparative sequence-based approach to predict fold switching in the universally conserved NusG transcription factor family, one member of which has a 50-residue regulatory subunit experimentally shown to switch between α-helical and β-sheet folds. Our approach predicts that 24% of sequences in this family undergo similar α-helix ⇌ β-sheet transitions. While these predictions cannot be reproduced by other state-of-the-art computational methods, they are confirmed by circular dichroism and nuclear magnetic resonance spectroscopy for 10 out of 10 sequence-diverse variants. This work suggests that fold switching may be a pervasive mechanism of transcriptional regulation in all kingdoms of life. Folded proteins are composed of secondary structures, α-helices and β-sheets, that are generally assumed to be stable. Here, the authors combine computational prediction with experimental validation to show that many sequence-diverse NusG protein domains switch completely from α-helix to β-sheet folds.
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28
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Dishman AF, Volkman BF. Design and discovery of metamorphic proteins. Curr Opin Struct Biol 2022; 74:102380. [PMID: 35561475 PMCID: PMC9664977 DOI: 10.1016/j.sbi.2022.102380] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/03/2022]
Abstract
Metamorphic proteins are single amino acid sequences that reversibly interconvert between multiple, dramatically different native structures, often with distinct functions. Since the discovery of the first metamorphic proteins in the early 2000s, several additional metamorphic proteins have been identified, and it was suggested that up to 4% of proteins in the PDB may switch folds. Metamorphic proteins have been found to share common features such as marginal thermostability and inconsistencies in predicted secondary structures. Outstanding challenges in the field include the search for more metamorphic proteins and the design of new proteins that switch folds. Identification of novel metamorphic proteins in nature will improve therapeutic targeting of fold-switching proteins involved in human pathology and will enhance the design of protein-based therapies. Designed fold switching proteins have applications as biosensors, molecular switches, molecular machines, and self-assembling systems.
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Affiliation(s)
- Acacia F Dishman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA; Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI, USA. https://twitter.com/@cacidish
| | - Brian F Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
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29
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Chakravarty D, Porter LL. AlphaFold2
fails to predict protein fold switching. Protein Sci 2022; 31:e4353. [DOI: 10.1002/pro.4353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/05/2022] [Accepted: 05/07/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Devlina Chakravarty
- National Library of Medicine, National Center for Biotechnology Information National Institutes of Health Bethesda Maryland USA
| | - Lauren L. Porter
- National Library of Medicine, National Center for Biotechnology Information National Institutes of Health Bethesda Maryland USA
- National Heart, Lung, and Blood Institute, Biochemistry and Biophysics Center National Institutes of Health Bethesda Maryland USA
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30
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Wang Y, Zhao L, Zhou X, Zhang J, Jiang J, Dong H. Global Fold Switching of the RafH Protein: Diverse Structures with a Conserved Pathway. J Phys Chem B 2022; 126:2979-2989. [PMID: 35438983 DOI: 10.1021/acs.jpcb.1c10965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It is generally believed that a protein's sequence uniquely determines its structure, the basis for a protein to perform biological functions. However, as a representative metamorphic protein, RfaH can be encoded by a single amino acid sequence into two distinct native state structures. Its C-terminal domain (CTD) either takes an all-α-helical configuration to pack tightly with its N-terminal domain (NTD), or the CTD disassociates from the NTD, transforms into an all-β-barrel fold, and further attaches to the ribosome, leaving the NTD exposed to bind RNA polymerases. Therefore, the RfaH protein couples transcription and translation processes. Although previous studies have provided a preliminary understanding of its function, the full course of the conformational change of RfaH-CTD at the atomic level is elusive. We used teDA2, a feature space-based enhanced sampling protocol, to explore the transformation of RfaH-CTD. We found that it undergoes a large-scale structural rearrangement, with characteristic spectra as the fingerprint, and a global unfolding transition with a tighter and energetically moderate molten globule-like nucleus formed in between. The formation of this nucleus limits the possible intermediate conformations, facilitates the formation of secondary and tertiary structures, and thus ensures the efficiency of transformation. The key features along the transition path disclosed from this work are likely associated with the evolution of RfaH, such that encoding a single sequence into multiple folds with distinct biological functions is energetically unhindered.
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Affiliation(s)
- Yiqiao Wang
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China.,School of Physics, National Laboratory of Solid State Microstructure, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Luyuan Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Xuejie Zhou
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Jian Zhang
- School of Physics, National Laboratory of Solid State Microstructure, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.,Institute for Brain Sciences, Nanjing University, Nanjing 210023, China
| | - Jun Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Hao Dong
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China.,Institute for Brain Sciences, Nanjing University, Nanjing 210023, China.,State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China.,Engineering Research Center of Protein and Peptide Medicine of Ministry of Education, Nanjing University, Nanjing 210023, China
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31
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Chakrabarti P, Chakravarty D. Intrinsically disordered proteins/regions and insight into their biomolecular interactions. Biophys Chem 2022; 283:106769. [DOI: 10.1016/j.bpc.2022.106769] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 12/20/2022]
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32
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Enderlein J, Sakhapov D, Gregor I, Croci M, Karedla N. Modeling charge separation in charged nanochannels for single-molecule electrometry. J Chem Phys 2022; 156:105104. [DOI: 10.1063/5.0074732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We model the transport of electrically charged solute molecules by a laminar flow within a nanoslit microfluidic channel with electrostatic surface potential. We derive the governing convection–diffusion equation, solve it numerically, and compare it with a Taylor–Aris-like approximation, which gives excellent results for small Péclet numbers. We discuss our results in light of designing an assay that can measure simultaneously the hydrodynamic size and electric charge of single molecules by tracking their motion in such nanoslit channels with electrostatic surface potential.
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Affiliation(s)
- Jörg Enderlein
- III. Institute of Physics–Biophysics, Georg August University, 37077 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), Georg August University, 37077 Göttingen, Germany
| | - Damir Sakhapov
- III. Institute of Physics–Biophysics, Georg August University, 37077 Göttingen, Germany
| | - Ingo Gregor
- III. Institute of Physics–Biophysics, Georg August University, 37077 Göttingen, Germany
| | - Matteo Croci
- Mathematical Institute, University of Oxford, Oxford OX2 6GG, United Kingdom
| | - Narain Karedla
- The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0FA, United Kingdom
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33
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Ghosh C, Jana B. Curious Case of MAD2 Protein: Diverse Folding Intermediates Leading to Alternate Native States. J Phys Chem B 2022; 126:1904-1916. [PMID: 35230837 DOI: 10.1021/acs.jpcb.2c00382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Anfinsen's dogma postulates that for one sequence there will be only one unique structure that is necessary for the functioning of the protein. However, over the years there have been a number of departures from this postulate. As far as function is considered, there are growing examples of proteins that "moonlight", perform multiple unrelated functions. With the discovery of intrinsically disordered proteins, morpheeins, chameleonic sequences, and metamorphic proteins that can switch folds, we have acquired a more nuanced understanding of protein folding and dynamics. Appearing to apparently contradict the classical folding paradigm, metamorphic proteins are considered exotic species. In this work, we have explored the free energy landscape and folding pathways of the metamorphic protein MAD2 which is an important component of the spindle checkpoint. It coexists in two alternate states: the inactive open state and the active closed state. Using a dual-basin structure-based model approach we have shown that a variety of intermediates and multiple pathways are available to MAD2 to fold into its alternate forms. This approach involves performing molecular dynamics simulations of coarse-grained models of MAD2 where the structural information regarding both of its native conformations is explicitly included in terms of their native contacts in the force field used. Detailed analyses have indicated that some of the contacts within the protein play a key role in determining which folding pathway will be selected and point to a probable long-range communication between the N and the C termini of the protein that seems to control its folding. Finally, our work also provides a rationale for the experimentally observed preference of the ΔC10 variant of MAD2 to exist in the open state.
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Affiliation(s)
- Catherine Ghosh
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Biman Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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34
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Affiliation(s)
- Andy LiWang
- University of California, Merced, California, USA
| | - Lauren L Porter
- National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA.,National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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35
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Mishra S, Looger LL, Porter LL. A sequence-based method for predicting extant fold switchers that undergo α-helix ↔ β-strand transitions. Biopolymers 2021; 112:e23471. [PMID: 34498740 PMCID: PMC8545793 DOI: 10.1002/bip.23471] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 12/21/2022]
Abstract
Extant fold‐switching proteins remodel their secondary structures and change their functions in response to cellular stimuli, regulating biological processes and affecting human health. Despite their biological importance, these proteins remain understudied. Predictive methods are needed to expedite the process of discovering and characterizing more of these shapeshifting proteins. Most previous approaches require a solved structure or all‐atom simulations, greatly constraining their use. Here, we propose a high‐throughput sequence‐based method for predicting extant fold switchers that transition from α‐helix in one conformation to β‐strand in the other. This method leverages two previous observations: (a) α‐helix ↔ β‐strand prediction discrepancies from JPred4 are a robust predictor of fold switching, and (b) the fold‐switching regions (FSRs) of some extant fold switchers have different secondary structure propensities when expressed by themselves (isolated FSRs) than when expressed within the context of their parent protein (contextualized FSRs). Combining these two observations, we ran JPred4 on 99‐fold‐switching proteins and found strong correspondence between predicted and experimentally observed α‐helix ↔ β‐strand discrepancies. To test the overall robustness of this finding, we randomly selected regions of proteins not expected to switch folds (single‐fold proteins) and found significantly fewer predicted α‐helix ↔ β‐strand discrepancies. Combining these discrepancies with the overall percentage of predicted secondary structure, we developed a classifier to identify extant fold switchers (Matthews correlation coefficient of .71). Although this classifier had a high false‐negative rate (7/17), its false‐positive rate was very low (2/136), suggesting that it can be used to predict a subset of extant fold switchers from a multitude of available genomic sequences.
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Affiliation(s)
- Soumya Mishra
- National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA.,Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, USA
| | - Loren L Looger
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia, USA
| | - Lauren L Porter
- National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA.,National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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36
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Porter LL. Predictable fold switching by the SARS-CoV-2 protein ORF9b. Protein Sci 2021; 30:1723-1729. [PMID: 33934422 PMCID: PMC8242659 DOI: 10.1002/pro.4097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 12/27/2022]
Abstract
Extant fold-switching proteins remodel their secondary structures and change their functions in response to environmental stimuli. These shapeshifting proteins regulate biological processes and are associated with a number of diseases, including tuberculosis, cancer, Alzheimer's, and autoimmune disorders. Thus, predictive methods are needed to identify more fold-switching proteins, especially since all naturally occurring instances have been discovered by chance. In response to this need, two high-throughput predictive methods have recently been developed. Here we test them on ORF9b, a newly discovered fold switcher and potential therapeutic target from the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Promisingly, both methods correctly indicate that ORF9b switches folds. We then tested the same two methods on ORF9b1, the ORF9b homolog from SARS-CoV-1. Again, both methods predict that ORF9b1 switches folds, a finding consistent with experimental binding studies. Together, these results (a) demonstrate that protein fold switching can be predicted using high-throughput computational approaches and (b) suggest that fold switching might be a general characteristic of ORF9b homologs.
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Affiliation(s)
- Lauren L. Porter
- National Library of MedicineNational Center for Biotechnology Information, National Institutes of HealthBethesdaMarylandUSA
- National Heart, Lung, and Blood InstituteBiochemistry and Biophysics Center, National Institutes of HealthBethesdaMarylandUSA
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37
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Dishman AF, He J, Volkman BF, Huppler AR. Metamorphic Protein Folding Encodes Multiple Anti- Candida Mechanisms in XCL1. Pathogens 2021; 10:pathogens10060762. [PMID: 34204234 PMCID: PMC8235156 DOI: 10.3390/pathogens10060762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/08/2021] [Accepted: 06/12/2021] [Indexed: 11/16/2022] Open
Abstract
Candida species cause serious infections requiring prolonged and sometimes toxic therapy. Antimicrobial proteins, such as chemokines, hold great interest as potential additions to the small number of available antifungal drugs. Metamorphic proteins reversibly switch between multiple different folded structures. XCL1 is a metamorphic, antimicrobial chemokine that interconverts between the conserved chemokine fold (an α–β monomer) and an alternate fold (an all-β dimer). Previous work has shown that human XCL1 kills C. albicans but has not assessed whether one or both XCL1 folds perform this activity. Here, we use structurally locked engineered XCL1 variants and Candida killing assays, adenylate kinase release assays, and propidium iodide uptake assays to demonstrate that both XCL1 folds kill Candida, but they do so via different mechanisms. Our results suggest that the alternate fold kills via membrane disruption, consistent with previous work, and the chemokine fold does not. XCL1 fold-switching thus provides a mechanism to regulate the XCL1 mode of antifungal killing, which could protect surrounding tissue from damage associated with fungal membrane disruption and could allow XCL1 to overcome candidal resistance by switching folds. This work provides inspiration for the future design of switchable, multifunctional antifungal therapeutics.
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Affiliation(s)
- Acacia F. Dishman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Medical Scientist Training Program, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jie He
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Correspondence: (B.F.V.); (A.R.H.)
| | - Anna R. Huppler
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
- Correspondence: (B.F.V.); (A.R.H.)
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38
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Morris DL, Tjandra N. Inducible fold-switching as a mechanism to fibrillate pro-apoptotic BCL-2 proteins. Biopolymers 2021; 112:e23424. [PMID: 33764501 DOI: 10.1002/bip.23424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/18/2021] [Accepted: 03/05/2021] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases often are associated with cellular dysregulation that results in premature cell death or apoptosis. A common example is the accumulation of amyloid plaques that promotes the excessive expression of p38 mitogen-activated protein kinase. The increased abundance of this enzyme leads to mass phosphorylation and activation of a protein from the B-cell lymphoma 2 (BCL-2) family, BAX. BAX is the central regulatory protein for mitochondrial outer membrane permeabilization (MOMP), a poration process that commits cells to apoptosis by releasing death-propagating factors from the mitochondria. Recent reports identify a naturally occurring peptide, Humanin (HN), that could block amyloid-beta-associated neuronal apoptosis by interacting with BCL-2 proteins. We recently showed humanin interaction leads to the amyloid-like fibrillation of BAX and a second BCL-2 family member, BID. We proposed this as a novel anti-apoptotic mechanism that inhibits pro-apoptotic BCL-2 proteins from initiating MOMP by sequestering them into fibrils, a heretofore unprecedented phenomenon that involves refolding globular BCL-2 proteins rapidly into fibrils where they undergo significant alpha-helix to beta-sheet fold-switching. Here we seek to further characterize the fibrillation and fold-switch in conditions that are known to induce amyloid fibrillation.
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Affiliation(s)
- Daniel L Morris
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Nico Tjandra
- Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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