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Kwon S, Andreas MP, Giessen TW. Structure and heterogeneity of a highly cargo-loaded encapsulin shell. J Struct Biol 2023; 215:108022. [PMID: 37657675 DOI: 10.1016/j.jsb.2023.108022] [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: 07/26/2023] [Revised: 08/26/2023] [Accepted: 08/28/2023] [Indexed: 09/03/2023]
Abstract
Encapsulins are self-assembling protein nanocompartments able to selectively encapsulate dedicated cargo enzymes. Encapsulins are widespread across bacterial and archaeal phyla and are involved in oxidative stress resistance, iron storage, and sulfur metabolism. Encapsulin shells exhibit icosahedral geometry and consist of 60, 180, or 240 identical protein subunits. Cargo encapsulation is mediated by the specific interaction of targeting peptides or domains, found in all cargo proteins, with the interior surface of the encapsulin shell during shell self-assembly. Here, we report the 2.53 Å cryo-EM structure of a heterologously produced and highly cargo-loaded T3 encapsulin shell from Myxococcus xanthus and explore the systems' structural heterogeneity. We find that exceedingly high cargo loading results in the formation of substantial amounts of distorted and aberrant shells, likely caused by a combination of unfavorable steric clashes of cargo proteins and shell conformational changes. Based on our cryo-EM structure, we determine and analyze the targeting peptide-shell binding mode. We find that both ionic and hydrophobic interactions mediate targeting peptide binding. Our results will guide future attempts at rationally engineering encapsulins for biomedical and biotechnological applications.
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Affiliation(s)
- Seokmu Kwon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael P Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Tobias W Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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2
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Kwon S, Andreas MP, Giessen TW. Structure and heterogeneity of a highly cargo-loaded encapsulin shell. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550694. [PMID: 37546724 PMCID: PMC10402063 DOI: 10.1101/2023.07.26.550694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Encapsulins are self-assembling protein nanocompartments able to selectively encapsulate dedicated cargo enzymes. Encapsulins are widespread across bacterial and archaeal phyla and are involved in oxidative stress resistance, iron storage, and sulfur metabolism. Encapsulin shells exhibit icosahedral geometry and consist of 60, 180, or 240 identical protein subunits. Cargo encapsulation is mediated by the specific interaction of targeting peptides or domains, found in all cargo proteins, with the interior surface of the encapsulin shell during shell self-assembly. Here, we report the 2.53 Å cryo-EM structure of a heterologously produced and highly cargo-loaded T3 encapsulin shell from Myxococcus xanthus and explore the systems' structural heterogeneity. We find that exceedingly high cargo loading results in the formation of substantial amounts of distorted and aberrant shells, likely caused by a combination of unfavorable steric clashes of cargo proteins and shell conformational changes. Based on our cryo-EM structure, we determine and analyze the targeting peptide-shell binding mode. We find that both ionic and hydrophobic interactions mediate targeting peptide binding. Our results will guide future attempts at rationally engineering encapsulins for biomedical and biotechnological applications.
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Affiliation(s)
- Seokmu Kwon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael P. Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Tobias W. Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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3
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Jeacock K, Chappard A, Gallagher KJ, Mackay CL, Kilgour DPA, Horrocks MH, Kunath T, Clarke DJ. Determining the Location of the α-Synuclein Dimer Interface Using Native Top-Down Fragmentation and Isotope Depletion-Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:847-856. [PMID: 36976861 PMCID: PMC10161212 DOI: 10.1021/jasms.2c00339] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
α-Synuclein (αSyn), a 140-residue intrinsically disordered protein, comprises the primary proteinaceous component of pathology-associated Lewy body inclusions in Parkinson's disease (PD). Due to its association with PD, αSyn is studied extensively; however, the endogenous structure and physiological roles of this protein are yet to be fully understood. Here, ion mobility-mass spectrometry and native top-down electron capture dissociation fragmentation have been used to elucidate the structural properties associated with a stable, naturally occurring dimeric species of αSyn. This stable dimer appears in both wild-type (WT) αSyn and the PD-associated variant A53E. Furthermore, we integrated a novel method for generating isotopically depleted protein into our native top-down workflow. Isotope depletion increases signal-to-noise ratio and reduces the spectral complexity of fragmentation data, enabling the monoisotopic peak of low abundant fragment ions to be observed. This enables the accurate and confident assignment of fragments unique to the αSyn dimer to be assigned and structural information about this species to be inferred. Using this approach, we were able to identify fragments unique to the dimer, which demonstrates a C-terminal to C-terminal interaction between the monomer subunits. The approach in this study holds promise for further investigation into the structural properties of endogenous multimeric species of αSyn.
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Affiliation(s)
- Kiani Jeacock
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Alexandre Chappard
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Kelly J Gallagher
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - C Logan Mackay
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - David P A Kilgour
- Chemistry and Forensics, Nottingham Trent University, Nottingham NG11 8NS, U.K
| | - Mathew H Horrocks
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Tilo Kunath
- Centre for Regenerative Medicine, Institute for Stem Cell Research, University of Edinburgh, Edinburgh EH16 4UU, U.K
| | - David J Clarke
- The EastCHEM School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
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4
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Bacterioferritin nanocage: Structure, biological function, catalytic mechanism, self-assembly and potential applications. Biotechnol Adv 2022; 61:108057. [DOI: 10.1016/j.biotechadv.2022.108057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/22/2022]
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5
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Sudarev VV, Dolotova SM, Bukhalovich SM, Bazhenov SV, Ryzhykau YL, Uversky VN, Bondarev NA, Osipov SD, Mikhailov AE, Kuklina DD, Murugova TN, Manukhov IV, Rogachev AV, Gordeliy VI, Gushchin IY, Kuklin AI, Vlasov AV. Ferritin self-assembly, structure, function, and biotechnological applications. Int J Biol Macromol 2022; 224:319-343. [DOI: 10.1016/j.ijbiomac.2022.10.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/28/2022] [Accepted: 10/13/2022] [Indexed: 11/05/2022]
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6
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Tasneem N, Szyszka TN, Jenner EN, Lau YH. How Pore Architecture Regulates the Function of Nanoscale Protein Compartments. ACS NANO 2022; 16:8540-8556. [PMID: 35583458 DOI: 10.1021/acsnano.2c02178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Self-assembling proteins can form porous compartments that adopt well-defined architectures at the nanoscale. In nature, protein compartments act as semipermeable barriers to enable spatial separation and organization of complex biochemical processes. The compartment pores play a key role in their overall function by selectively controlling the influx and efflux of important biomolecular species. By engineering the pores, the functionality of compartments can be tuned to facilitate non-native applications, such as artificial nanoreactors for catalysis. In this review, we analyze how protein structure determines the porosity and impacts the function of both native and engineered compartments, highlighting the wealth of structural data recently obtained by cryo-EM and X-ray crystallography. Through this analysis, we offer perspectives on how current structural insights can inform future studies into the design of artificial protein compartments as nanoreactors with tunable porosity and function.
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Affiliation(s)
- Nuren Tasneem
- School of Chemistry, The University of Sydney, Eastern Avenue, Camperdown, New South Wales 2006, Australia
| | - Taylor N Szyszka
- School of Chemistry, The University of Sydney, Eastern Avenue, Camperdown, New South Wales 2006, Australia
- University of Sydney Nano Institute, Camperdown, New South Wales 2006, Australia
| | - Eric N Jenner
- School of Chemistry, The University of Sydney, Eastern Avenue, Camperdown, New South Wales 2006, Australia
| | - Yu Heng Lau
- School of Chemistry, The University of Sydney, Eastern Avenue, Camperdown, New South Wales 2006, Australia
- University of Sydney Nano Institute, Camperdown, New South Wales 2006, Australia
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Abstract
Subcellular compartmentalization is a defining feature of all cells. In prokaryotes, compartmentalization is generally achieved via protein-based strategies. The two main classes of microbial protein compartments are bacterial microcompartments and encapsulin nanocompartments. Encapsulins self-assemble into proteinaceous shells with diameters between 24 and 42 nm and are defined by the viral HK97-fold of their shell protein. Encapsulins have the ability to encapsulate dedicated cargo proteins, including ferritin-like proteins, peroxidases, and desulfurases. Encapsulation is mediated by targeting sequences present in all cargo proteins. Encapsulins are found in many bacterial and archaeal phyla and have been suggested to play roles in iron storage, stress resistance, sulfur metabolism, and natural product biosynthesis. Phylogenetic analyses indicate that they share a common ancestor with viral capsid proteins. Many pathogens encode encapsulins, and recent evidence suggests that they may contribute toward pathogenicity. The existing information on encapsulin structure, biochemistry, biological function, and biomedical relevance is reviewed here.
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Affiliation(s)
- Tobias W. Giessen
- Departments of Biomedical Engineering and Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Eren E, Wang B, Winkler DC, Watts NR, Steven AC, Wingfield PT. Structural characterization of the Myxococcus xanthus encapsulin and ferritin-like cargo system gives insight into its iron storage mechanism. Structure 2022; 30:551-563.e4. [PMID: 35150605 PMCID: PMC8995368 DOI: 10.1016/j.str.2022.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 11/22/2021] [Accepted: 01/18/2022] [Indexed: 10/19/2022]
Abstract
Encapsulins are bacterial organelle-like cages involved in various aspects of metabolism, especially protection from oxidative stress. They can serve as vehicles for a wide range of medical applications. Encapsulin shell proteins are structurally similar to HK97 bacteriophage capsid protein and their function depends on the encapsulated cargos. The Myxococcus xanthus encapsulin system comprises EncA and three cargos: EncB, EncC, and EncD. EncB and EncC are similar to bacterial ferritins that can oxidize Fe+2 to less toxic Fe+3. We analyzed EncA, EncB, and EncC by cryo-EM and X-ray crystallography. Cryo-EM shows that EncA cages can have T = 3 and T = 1 symmetry and that EncA T = 1 has a unique protomer arrangement. Also, we define EncB and EncC binding sites on EncA. X-ray crystallography of EncB and EncC reveals conformational changes at the ferroxidase center and additional metal binding sites, suggesting a mechanism for Fe oxidation and storage within the encapsulin shell.
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Ross J, McIver Z, Lambert T, Piergentili C, Bird JE, Gallagher KJ, Cruickshank FL, James P, Zarazúa-Arvizu E, Horsfall LE, Waldron KJ, Wilson MD, Mackay CL, Baslé A, Clarke DJ, Marles-Wright J. Pore dynamics and asymmetric cargo loading in an encapsulin nanocompartment. SCIENCE ADVANCES 2022; 8:eabj4461. [PMID: 35080974 PMCID: PMC8791618 DOI: 10.1126/sciadv.abj4461] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Encapsulins are protein nanocompartments that house various cargo enzymes, including a family of decameric ferritin-like proteins. Here, we study a recombinant Haliangium ochraceum encapsulin:encapsulated ferritin complex using cryo-electron microscopy and hydrogen/deuterium exchange mass spectrometry to gain insight into the structural relationship between the encapsulin shell and its protein cargo. An asymmetric single-particle reconstruction reveals four encapsulated ferritin decamers in a tetrahedral arrangement within the encapsulin nanocompartment. This leads to a symmetry mismatch between the protein cargo and the icosahedral encapsulin shell. The encapsulated ferritin decamers are offset from the interior face of the encapsulin shell. Using hydrogen/deuterium exchange mass spectrometry, we observed the dynamic behavior of the major fivefold pore in the encapsulin shell and show the pore opening via the movement of the encapsulin A-domain. These data will accelerate efforts to engineer the encapsulation of heterologous cargo proteins and to alter the permeability of the encapsulin shell via pore modifications.
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Affiliation(s)
- Jennifer Ross
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Zak McIver
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Thomas Lambert
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Cecilia Piergentili
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jasmine Emma Bird
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Kelly J. Gallagher
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Faye L. Cruickshank
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Patrick James
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | | | - Louise E. Horsfall
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Kevin J. Waldron
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Marcus D. Wilson
- Wellcome Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JR, UK
| | - C. Logan Mackay
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Arnaud Baslé
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David J. Clarke
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Jon Marles-Wright
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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10
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Wiryaman T, Toor N. Recent advances in the structural biology of encapsulin bacterial nanocompartments. J Struct Biol X 2022; 6:100062. [PMID: 35146412 PMCID: PMC8802124 DOI: 10.1016/j.yjsbx.2022.100062] [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: 10/08/2021] [Revised: 01/14/2022] [Accepted: 01/20/2022] [Indexed: 02/05/2023] Open
Abstract
Large capsid-like nanocompartments called encapsulins are common in bacteria and archaea and contain cargo proteins with diverse functions. Advances in cryo-electron microscopy have enabled structure determination of many encapsulins in recent years. Here we summarize findings from recent encapsulin structures that have significant implications for their biological roles. We also compare important features such as the E-loop, cargo-peptide binding site, and the fivefold axis channel in different structures. In addition, we describe the discovery of a flavin-binding pocket within the encapsulin shell that may reveal a role for this nanocompartment in iron metabolism.
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Affiliation(s)
| | - Navtej Toor
- University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
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11
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Wiryaman T, Toor N. Cryo-EM structure of a thermostable bacterial nanocompartment. IUCRJ 2021; 8:342-350. [PMID: 33953921 PMCID: PMC8086157 DOI: 10.1107/s2052252521001949] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/18/2021] [Indexed: 05/21/2023]
Abstract
Protein nanocompartments are widespread in bacteria and archaea, but their functions are not yet well understood. Here, the cryo-EM structure of a nanocompartment from the thermophilic bacterium Thermotoga maritima is reported at 2.0 Å resolution. The high resolution of this structure shows that interactions in the E-loop domain may be important for the thermostability of the nanocompartment assembly. Also, the channels at the fivefold axis, threefold axis and dimer interface are assessed for their ability to transport iron. Finally, an unexpected flavin ligand was identified on the exterior of the shell, indicating that this nanocompartment may also play a direct role in iron metabolism.
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Affiliation(s)
- Timothy Wiryaman
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Navtej Toor
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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