1
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Kwon S, Andreas MP, Giessen TW. Pore Engineering as a General Strategy to Improve Protein-Based Enzyme Nanoreactor Performance. ACS NANO 2024; 18:25740-25753. [PMID: 39226211 DOI: 10.1021/acsnano.4c08186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Enzyme nanoreactors are nanoscale compartments consisting of encapsulated enzymes and a selectively permeable barrier. Sequestration and colocalization of enzymes can increase catalytic activity, stability, and longevity, highly desirable features for many biotechnological and biomedical applications of enzyme catalysts. One promising strategy to construct enzyme nanoreactors is to repurpose protein nanocages found in nature. However, protein-based enzyme nanoreactors often exhibit decreased catalytic activity, partially caused by a mismatch of protein shell selectivity and the substrate requirements of encapsulated enzymes. No broadly applicable and modular protein-based nanoreactor platform is currently available. Here, we introduce a pore-engineered universal enzyme nanoreactor platform based on encapsulins-microbial self-assembling protein nanocompartments with programmable and selective enzyme packaging capabilities. We structurally characterize our protein shell designs via cryo-electron microscopy and highlight their polymorphic nature. Through fluorescence polarization assays, we show their improved molecular flux behavior and highlight their expanded substrate range via a number of proof-of-concept enzyme nanoreactor designs. This work lays the foundation for utilizing our encapsulin-based nanoreactor platform for diverse future biotechnological and biomedical applications.
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Affiliation(s)
- Seokmu Kwon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Michael P Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Tobias W Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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2
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Ryngajłło M, Cielecka I, Daroch M. Complete genome sequence and transcriptome response to vitamin C supplementation of Novacetimonas hansenii SI1 - producer of highly-stretchable cellulose. N Biotechnol 2024; 81:57-68. [PMID: 38531507 DOI: 10.1016/j.nbt.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 02/28/2024] [Accepted: 03/23/2024] [Indexed: 03/28/2024]
Abstract
Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin C in the culture medium increases the porosity of the membranes and their stretchability making them highly moldable. To better understand the genetic background of this strain, we obtained its complete genome sequence using a hybrid sequencing and assembly strategy. We described the functional regions in the genome which are important for the synthesis of BNC and acetan-like II polymer. We next investigated the effect of 1% vitamin C supplementation on the global gene expression profile using RNA sequencing. Our transcriptomic readouts imply that vitamin C functions mainly as a reducing agent. We found that the changes in cellular redox status are balanced by strong repression of the sulfur assimilation pathway. Moreover, in the reduced conditions, glucose oxidation is decreased and alternative pathways for energy generation, such as acetate accumulation, are activated. The presence of vitamin C negatively influences acetan-like II polymer biosynthesis, which may explain the lowered yield and changed mechanical properties of BNC. The results of this study enrich the functional characteristics of the genomes of the efficient producers of the N. hansenii species. Improved understanding of the adaptation to the presence of vitamin C at the molecular level has important guiding significance for influencing the biosynthesis of BNC and its morphology.
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Affiliation(s)
- Małgorzata Ryngajłło
- Institute of Molecular and Industrial Biotechnology, Lodz University of Technology, B. Stefanowskiego 2/22, Lodz 90-537, Poland.
| | - Izabela Cielecka
- Institute of Molecular and Industrial Biotechnology, Lodz University of Technology, B. Stefanowskiego 2/22, Lodz 90-537, Poland
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China
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3
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Bhattacharya S, Jenkins MC, Keshavarz-Joud P, Bourque AR, White K, Alvarez Barkane AM, Bryksin AV, Hernandez C, Kopylov M, Finn M. Heterologous Prime-Boost with Immunologically Orthogonal Protein Nanoparticles for Peptide Immunofocusing. ACS NANO 2024; 18:20083-20100. [PMID: 39041587 PMCID: PMC11308774 DOI: 10.1021/acsnano.4c00949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/24/2024]
Abstract
Protein nanoparticles are effective platforms for antigen presentation and targeting effector immune cells in vaccine development. Encapsulins are a class of protein-based microbial nanocompartments that self-assemble into icosahedral structures with external diameters ranging from 24 to 42 nm. Encapsulins from Myxococcus xanthus were designed to package bacterial RNA when produced in E. coli and were shown to have immunogenic and self-adjuvanting properties enhanced by this RNA. We genetically incorporated a 20-mer peptide derived from a mutant strain of the SARS-CoV-2 receptor binding domain (RBD) into the encapsulin protomeric coat protein for presentation on the exterior surface of the particle, inducing the formation of several nonicosahedral structures that were characterized by cryogenic electron microscopy. This immunogen elicited conformationally relevant humoral responses to the SARS-CoV-2 RBD. Immunological recognition was enhanced when the same peptide was presented in a heterologous prime/boost vaccination strategy using the engineered encapsulin and a previously reported variant of the PP7 virus-like particle, leading to the development of a selective antibody response against a SARS-CoV-2 RBD point mutant. While generating epitope-focused antibody responses is an interplay between inherent vaccine properties and B/T cells, here we demonstrate the use of orthogonal nanoparticles to fine-tune the control of epitope focusing.
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Affiliation(s)
- Sonia Bhattacharya
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Matthew C. Jenkins
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Parisa Keshavarz-Joud
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Alisyn Retos Bourque
- Parker
H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Keiyana White
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
| | - Amina Maria Alvarez Barkane
- Parker
H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Anton V. Bryksin
- Parker
H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Carolina Hernandez
- New
York Structural Biology Center, New York, New York 10027, United States
| | - Mykhailo Kopylov
- New
York Structural Biology Center, New York, New York 10027, United States
| | - M.G. Finn
- School
of Chemistry and Biochemistry, Georgia Institute
of Technology, Atlanta, Georgia 30332, United States
- School
of Biological Sciences, Georgia Institute
of Technology, Atlanta, Georgia 30332, United
States
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4
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Lučić M, Allport T, Clarke TA, Williams LJ, Wilson MT, Chaplin AK, Worrall JAR. The oligomeric states of dye-decolorizing peroxidases from Streptomyces lividans and their implications for mechanism of substrate oxidation. Protein Sci 2024; 33:e5073. [PMID: 38864770 PMCID: PMC11168072 DOI: 10.1002/pro.5073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/18/2024] [Accepted: 05/25/2024] [Indexed: 06/13/2024]
Abstract
A common evolutionary mechanism in biology to drive function is protein oligomerization. In prokaryotes, the symmetrical assembly of repeating protein units to form homomers is widespread, yet consideration in vitro of whether such assemblies have functional or mechanistic consequences is often overlooked. Dye-decolorizing peroxidases (DyPs) are one such example, where their dimeric α + β barrel units can form various oligomeric states, but the oligomer influence, if any, on mechanism and function has received little attention. In this work, we have explored the oligomeric state of three DyPs found in Streptomyces lividans, each with very different mechanistic behaviors in their reactions with hydrogen peroxide and organic substrates. Using analytical ultracentrifugation, we reveal that except for one of the A-type DyPs where only a single sedimenting species is detected, oligomer states ranging from homodimers to dodecamers are prevalent in solution. Using cryo-EM on preparations of the B-type DyP, we determined a 3.02 Å resolution structure of a hexamer assembly that corresponds to the dominant oligomeric state in solution as determined by analytical ultracentrifugation. Furthermore, cryo-EM data detected sub-populations of higher-order oligomers, with one of these formed by an arrangement of two B-type DyP hexamers to give a dodecamer assembly. Our solution and structural insights of these oligomer states provide a new framework to consider previous mechanistic studies of these DyP members and are discussed in terms of long-range electron transfer for substrate oxidation and in the "storage" of oxidizable equivalents on the heme until a two-electron donor is available.
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Affiliation(s)
- Marina Lučić
- School of Life SciencesUniversity of EssexColchesterUK
| | - Thomas Allport
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell BiologyUniversity of LeicesterLeicesterUK
| | | | | | | | - Amanda K. Chaplin
- Leicester Institute for Structural and Chemical Biology, Department of Molecular and Cell BiologyUniversity of LeicesterLeicesterUK
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5
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Trettel DS, Kerfeld CA, Gonzalez-Esquer CR. Dynamic structural determinants in bacterial microcompartment shells. Curr Opin Microbiol 2024; 80:102497. [PMID: 38909546 DOI: 10.1016/j.mib.2024.102497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/07/2024] [Accepted: 06/03/2024] [Indexed: 06/25/2024]
Abstract
Bacterial microcompartments (BMCs) are polyhedral structures that segregate enzymatic cargo from the cytosol via encapsulation within a protein shell. Unlike other biological polyhedra, such as viral capsids and encapsulins, BMC shells can exhibit a highly advantageous structural and functional plasticity, conforming to a variety of anabolic (CO2 fixation in carboxysomes) and catabolic (nutrient assimilation in metabolosomes) roles. Consequently, understanding the subunit properties and associated protein-protein interaction processes that guide shell assembly and function is a necessary step to fully harness BMCs as modular, biotechnological nanomachines. Here, we describe the recent insights into the dynamics of structural features of the key BMC domain (Pfam00936)-containing proteins, which serve as a structural template for BMC-H and BMC-T shell building blocks.
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Affiliation(s)
- Daniel S Trettel
- Los Alamos National Laboratory, Bioscience Division, Microbial and Biome Sciences group, Los Alamos, NM, USA
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Cesar R Gonzalez-Esquer
- Los Alamos National Laboratory, Bioscience Division, Microbial and Biome Sciences group, Los Alamos, NM, USA.
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6
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Van de Steen A, Wilkinson HC, Dalby PA, Frank S. Encapsulation of Transketolase into In Vitro-Assembled Protein Nanocompartments Improves Thermal Stability. ACS APPLIED BIO MATERIALS 2024; 7:3660-3674. [PMID: 38835217 PMCID: PMC11190991 DOI: 10.1021/acsabm.3c01153] [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: 11/29/2023] [Revised: 05/16/2024] [Accepted: 05/20/2024] [Indexed: 06/06/2024]
Abstract
Protein compartments offer definitive structures with a large potential design space that are of particular interest for green chemistry and therapeutic applications. One family of protein compartments, encapsulins, are simple prokaryotic nanocompartments that self-assemble from a single monomer into selectively permeable cages of between 18 and 42 nm. Over the past decade, encapsulins have been developed for a diverse application portfolio utilizing their defined cargo loading mechanisms and repetitive surface display. Although it has been demonstrated that encapsulation of non-native cargo proteins provides protection from protease activity, the thermal effects arising from enclosing cargo within encapsulins remain poorly understood. This study aimed to establish a methodology for loading a reporter protein into thermostable encapsulins to determine the resulting stability change of the cargo. Building on previous in vitro reassembly studies, we first investigated the effectiveness of in vitro reassembly and cargo-loading of two size classes of encapsulins Thermotoga maritima T = 1 and Myxococcus xanthus T = 3, using superfolder Green Fluorescent Protein. We show that the empty T. maritima capsid reassembles with higher yield than the M. xanthus capsid and that in vitro loading promotes the formation of the M. xanthus T = 3 capsid form over the T = 1 form, while overloading with cargo results in malformed T. maritima T = 1 encapsulins. For the stability study, a Förster resonance energy transfer (FRET)-probed industrially relevant enzyme cargo, transketolase, was then loaded into the T. maritima encapsulin. Our results show that site-specific orthogonal FRET labels can reveal changes in thermal unfolding of encapsulated cargo, suggesting that in vitro loading of transketolase into the T. maritima T = 1 encapsulin shell increases the thermal stability of the enzyme. This work supports the move toward fully harnessing structural, spatial, and functional control of in vitro assembled encapsulins with applications in cargo stabilization.
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Affiliation(s)
| | | | - Paul A. Dalby
- Department of Biochemical
Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, U.K.
| | - Stefanie Frank
- Department of Biochemical
Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, U.K.
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7
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Eren E, Watts NR, Montecinos F, Wingfield PT. Encapsulated Ferritin-like Proteins: A Structural Perspective. Biomolecules 2024; 14:624. [PMID: 38927029 PMCID: PMC11202242 DOI: 10.3390/biom14060624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Encapsulins are self-assembling nano-compartments that naturally occur in bacteria and archaea. These nano-compartments encapsulate cargo proteins that bind to the shell's interior through specific recognition sequences and perform various metabolic processes. Encapsulation enables organisms to perform chemical reactions without exposing the rest of the cell to potentially harmful substances while shielding cargo molecules from degradation and other adverse effects of the surrounding environment. One particular type of cargo protein, the ferritin-like protein (FLP), is the focus of this review. Encapsulated FLPs are members of the ferritin-like protein superfamily, and they play a crucial role in converting ferrous iron (Fe+2) to ferric iron (Fe+3), which is then stored inside the encapsulin in mineralized form. As such, FLPs regulate iron homeostasis and protect organisms against oxidative stress. Recent studies have demonstrated that FLPs have tremendous potential as biosensors and bioreactors because of their ability to catalyze the oxidation of ferrous iron with high specificity and efficiency. Moreover, they have been investigated as potential targets for therapeutic intervention in cancer drug development and bacterial pathogenesis. Further research will likely lead to new insights and applications for these remarkable proteins in biomedicine and biotechnology.
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Affiliation(s)
| | | | | | - Paul T. Wingfield
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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8
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Eren E, Watts NR, Conway JF, Wingfield PT. Myxococcus xanthus encapsulin cargo protein EncD is a flavin-binding protein with ferric reductase activity. Proc Natl Acad Sci U S A 2024; 121:e2400426121. [PMID: 38748579 PMCID: PMC11126975 DOI: 10.1073/pnas.2400426121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024] Open
Abstract
Encapsulins are protein nanocompartments that regulate cellular metabolism in several bacteria and archaea. Myxococcus xanthus encapsulins protect the bacterial cells against oxidative stress by sequestering cytosolic iron. These encapsulins are formed by the shell protein EncA and three cargo proteins: EncB, EncC, and EncD. EncB and EncC form rotationally symmetric decamers with ferroxidase centers (FOCs) that oxidize Fe+2 to Fe+3 for iron storage in mineral form. However, the structure and function of the third cargo protein, EncD, have yet to be determined. Here, we report the x-ray crystal structure of EncD in complex with flavin mononucleotide. EncD forms an α-helical hairpin arranged as an antiparallel dimer, but unlike other flavin-binding proteins, it has no β-sheet, showing that EncD and its homologs represent a unique class of bacterial flavin-binding proteins. The cryo-EM structure of EncA-EncD encapsulins confirms that EncD binds to the interior of the EncA shell via its C-terminal targeting peptide. With only 100 amino acids, the EncD α-helical dimer forms the smallest flavin-binding domain observed to date. Unlike EncB and EncC, EncD lacks a FOC, and our biochemical results show that EncD instead is a NAD(P)H-dependent ferric reductase, indicating that the M. xanthus encapsulins act as an integrated system for iron homeostasis. Overall, this work contributes to our understanding of bacterial metabolism and could lead to the development of technologies for iron biomineralization and the production of iron-containing materials for the treatment of various diseases associated with oxidative stress.
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Affiliation(s)
- Elif Eren
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD20892
| | - Norman R. Watts
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD20892
| | - James F. Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA15260
| | - Paul T. Wingfield
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD20892
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9
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Dutcher CA, Andreas MP, Giessen TW. A two-component quasi-icosahedral protein nanocompartment with variable shell composition and irregular tiling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591138. [PMID: 38712103 PMCID: PMC11071501 DOI: 10.1101/2024.04.25.591138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Protein shells or capsids are a widespread form of compartmentalization in nature. Viruses use protein capsids to protect and transport their genomes while many cellular organisms use protein shells for varied metabolic purposes. These protein-based compartments often exhibit icosahedral symmetry and consist of a small number of structural components with defined roles. Encapsulins are a prevalent protein-based compartmentalization strategy in prokaryotes. All encapsulins studied thus far consist of a single shell protein that adopts the viral HK97-fold. Here, we report the characterization of a Family 2B two-component encapsulin from Streptomyces lydicus. We show the differential assembly behavior of the two shell components and demonstrate their ability to co-assemble into mixed shells with variable shell composition. We determined the structures of both shell proteins using cryo-electron microscopy. Using 3D-classification and crosslinking studies, we highlight the irregular tiling of mixed shells. Our work expands the known assembly modes of HK97-fold proteins and lays the foundation for future functional and engineering studies on two-component encapsulins.
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Affiliation(s)
- Cassandra A. Dutcher
- Department of Biological Chemistry, University of Michigan Medical School, 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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10
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Andreas MP, Giessen TW. The biosynthesis of the odorant 2-methylisoborneol is compartmentalized inside a protein shell. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.23.590730. [PMID: 38712110 PMCID: PMC11071394 DOI: 10.1101/2024.04.23.590730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Terpenoids are the largest class of natural products, found across all domains of life. One of the most abundant bacterial terpenoids is the volatile odorant 2-methylisoborneol (2-MIB), partially responsible for the earthy smell of soil and musty taste of contaminated water. Many bacterial 2-MIB biosynthetic gene clusters were thought to encode a conserved transcription factor, named EshA in the model soil bacterium Streptomyces griseus . Here, we revise the function of EshA, now referred to as Sg Enc, and show that it is a Family 2B encapsulin shell protein. Using cryo-electron microscopy, we find that Sg Enc forms an icosahedral protein shell and encapsulates 2-methylisoborneol synthase (2-MIBS) as a cargo protein. Sg Enc contains a cyclic adenosine monophosphate (cAMP) binding domain (CBD)-fold insertion and a unique metal-binding domain, both displayed on the shell exterior. We show that Sg Enc CBDs do not bind cAMP. We find that 2-MIBS cargo loading is mediated by an N-terminal disordered cargo-loading domain and that 2-MIBS activity and Sg Enc shell structure are not modulated by cAMP. Our work redefines the function of EshA and establishes Family 2B encapsulins as cargo-loaded protein nanocompartments involved in secondary metabolite biosynthesis.
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11
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Jones JA, Andreas MP, Giessen TW. Structural basis for peroxidase encapsulation inside the encapsulin from the Gram-negative pathogen Klebsiella pneumoniae. Nat Commun 2024; 15:2558. [PMID: 38519509 PMCID: PMC10960027 DOI: 10.1038/s41467-024-46880-x] [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: 09/21/2023] [Accepted: 03/12/2024] [Indexed: 03/25/2024] Open
Abstract
Encapsulins are self-assembling protein nanocompartments capable of selectively encapsulating dedicated cargo proteins, including enzymes involved in iron storage, sulfur metabolism, and stress resistance. They represent a unique compartmentalization strategy used by many pathogens to facilitate specialized metabolic capabilities. Encapsulation is mediated by specific cargo protein motifs known as targeting peptides (TPs), though the structural basis for encapsulation of the largest encapsulin cargo class, dye-decolorizing peroxidases (DyPs), is currently unknown. Here, we characterize a DyP-containing encapsulin from the enterobacterial pathogen Klebsiella pneumoniae. By combining cryo-electron microscopy with TP and TP-binding site mutagenesis, we elucidate the molecular basis for cargo encapsulation. TP binding is mediated by cooperative hydrophobic and ionic interactions as well as shape complementarity. Our results expand the molecular understanding of enzyme encapsulation inside protein nanocompartments and lay the foundation for rationally modulating encapsulin cargo loading for biomedical and biotechnological applications.
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Affiliation(s)
- Jesse A Jones
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael P Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Tobias W Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.
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12
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Bhattacharya S, Jenkins MC, Keshavarz-Joud P, Bourque AR, White K, Alvarez Barkane AM, Bryksin AV, Hernandez C, Kopylov M, Finn MG. Heterologous Prime-Boost with Immunologically Orthogonal Protein Nanoparticles for Peptide Immunofocusing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.24.581861. [PMID: 38464232 PMCID: PMC10925081 DOI: 10.1101/2024.02.24.581861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Protein nanoparticles are effective platforms for antigen presentation and targeting effector immune cells in vaccine development. Encapsulins are a class of protein-based microbial nanocompartments that self-assemble into icosahedral structures with external diameters ranging from 24 to 42 nm. Encapsulins from Mxyococcus xanthus were designed to package bacterial RNA when produced in E. coli and were shown to have immunogenic and self-adjuvanting properties enhanced by this RNA. We genetically incorporated a 20-mer peptide derived from a mutant strain of the SARS-CoV-2 receptor binding domain (RBD) into the encapsulin protomeric coat protein for presentation on the exterior surface of the particle. This immunogen elicited conformationally-relevant humoral responses to the SARS-CoV-2 RBD. Immunological recognition was enhanced when the same peptide was presented in a heterologous prime/boost vaccination strategy using the engineered encapsulin and a previously reported variant of the PP7 virus-like particle, leading to the development of a selective antibody response against a SARS-CoV-2 RBD point mutant. While generating epitope-focused antibody responses is an interplay between inherent vaccine properties and B/T cells, here we demonstrate the use of orthogonal nanoparticles to fine-tune the control of epitope focusing.
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Affiliation(s)
- Sonia Bhattacharya
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Matthew C Jenkins
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Parisa Keshavarz-Joud
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alisyn Retos Bourque
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Keiyana White
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Amina M Alvarez Barkane
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Anton V Bryksin
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | | | - Mykhailo Kopylov
- New York Structural Biology Center, New York, New York, 10027, USA
| | - M G Finn
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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13
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Benisch R, Andreas MP, Giessen TW. A widespread bacterial protein compartment sequesters and stores elemental sulfur. SCIENCE ADVANCES 2024; 10:eadk9345. [PMID: 38306423 PMCID: PMC10836720 DOI: 10.1126/sciadv.adk9345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 01/03/2024] [Indexed: 02/04/2024]
Abstract
Subcellular compartments often serve to store nutrients or sequester labile or toxic compounds. As bacteria mostly do not possess membrane-bound organelles, they often have to rely on protein-based compartments. Encapsulins are one of the most prevalent protein-based compartmentalization strategies found in prokaryotes. Here, we show that desulfurase encapsulins can sequester and store large amounts of crystalline elemental sulfur. We determine the 1.78-angstrom cryo-EM structure of a 24-nanometer desulfurase-loaded encapsulin. Elemental sulfur crystals can be formed inside the encapsulin shell in a desulfurase-dependent manner with l-cysteine as the sulfur donor. Sulfur accumulation can be influenced by the concentration and type of sulfur source in growth medium. The selectively permeable protein shell allows the storage of redox-labile elemental sulfur by excluding cellular reducing agents, while encapsulation substantially improves desulfurase activity and stability. These findings represent an example of a protein compartment able to accumulate and store elemental sulfur.
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Affiliation(s)
- Robert Benisch
- Program in Chemical Biology, 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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14
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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: 11] [Impact Index Per Article: 11.0] [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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15
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Fung HKH, Hayashi Y, Salo VT, Babenko A, Zagoriy I, Brunner A, Ellenberg J, Müller CW, Cuylen-Haering S, Mahamid J. Genetically encoded multimeric tags for subcellular protein localization in cryo-EM. Nat Methods 2023; 20:1900-1908. [PMID: 37932397 PMCID: PMC10703698 DOI: 10.1038/s41592-023-02053-0] [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: 12/10/2022] [Accepted: 09/19/2023] [Indexed: 11/08/2023]
Abstract
Cryo-electron tomography (cryo-ET) allows for label-free high-resolution imaging of macromolecular assemblies in their native cellular context. However, the localization of macromolecules of interest in tomographic volumes can be challenging. Here we present a ligand-inducible labeling strategy for intracellular proteins based on fluorescent, 25-nm-sized, genetically encoded multimeric particles (GEMs). The particles exhibit recognizable structural signatures, enabling their automated detection in cryo-ET data by convolutional neural networks. The coupling of GEMs to green fluorescent protein-tagged macromolecules of interest is triggered by addition of a small-molecule ligand, allowing for time-controlled labeling to minimize disturbance to native protein function. We demonstrate the applicability of GEMs for subcellular-level localization of endogenous and overexpressed proteins across different organelles in human cells using cryo-correlative fluorescence and cryo-ET imaging. We describe means for quantifying labeling specificity and efficiency, and for systematic optimization for rare and abundant protein targets, with emphasis on assessing the potential effects of labeling on protein function.
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Affiliation(s)
- Herman K H Fung
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yuki Hayashi
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Anastasiia Babenko
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Ievgeniia Zagoriy
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Andreas Brunner
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Faculty of Biosciences, Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Sara Cuylen-Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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16
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Quinton AR, McDowell HB, Hoiczyk E. Encapsulins: Nanotechnology's future in a shell. ADVANCES IN APPLIED MICROBIOLOGY 2023; 125:1-48. [PMID: 38783722 DOI: 10.1016/bs.aambs.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Encapsulins, virus capsid-like bacterial nanocompartments have emerged as promising tools in medicine, imaging, and material sciences. Recent work has shown that these protein-bound icosahedral 'organelles' possess distinct properties that make them exceptionally usable for nanotechnology applications. A key factor contributing to their appeal is their ability to self-assemble, coupled with their capacity to encapsulate a wide range of cargos. Their genetic manipulability, stability, biocompatibility, and nano-size further enhance their utility, offering outstanding possibilities for practical biotechnology applications. In particular, their amenability to engineering has led to their extensive modification, including the packaging of non-native cargos and the utilization of the shell surface for displaying immunogenic or targeting proteins and peptides. This inherent versatility, combined with the ease of expressing encapsulins in heterologous hosts, promises to provide broad usability. Although mostly not yet commercialized, encapsulins have started to demonstrate their vast potential for biotechnology, from drug delivery to biofuel production and the synthesis of valuable inorganic materials. In this review, we will initially discuss the structure, function and diversity of encapsulins, which form the basis for these emerging applications, before reviewing ongoing practical uses and highlighting promising applications in medicine, engineering and environmental sciences.
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Affiliation(s)
- Amy Ruth Quinton
- School of Biosciences, The Krebs Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Harry Benjamin McDowell
- School of Biosciences, The Krebs Institute, The University of Sheffield, Sheffield, United Kingdom
| | - Egbert Hoiczyk
- School of Biosciences, The Krebs Institute, The University of Sheffield, Sheffield, United Kingdom.
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17
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Jones JA, Andreas MP, Giessen TW. Structural basis for peroxidase encapsulation in a protein nanocompartment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.18.558302. [PMID: 37790520 PMCID: PMC10542125 DOI: 10.1101/2023.09.18.558302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Encapsulins are self-assembling protein nanocompartments capable of selectively encapsulating dedicated cargo proteins, including enzymes involved in iron storage, sulfur metabolism, and stress resistance. They represent a unique compartmentalization strategy used by many pathogens to facilitate specialized metabolic capabilities. Encapsulation is mediated by specific cargo protein motifs known as targeting peptides (TPs), though the structural basis for encapsulation of the largest encapsulin cargo class, dye-decolorizing peroxidases (DyPs), is currently unknown. Here, we characterize a DyP-containing encapsulin from the enterobacterial pathogen Klebsiella pneumoniae. By combining cryo-electron microscopy with TP mutagenesis, we elucidate the molecular basis for cargo encapsulation. TP binding is mediated by cooperative hydrophobic and ionic interactions as well as shape complementarity. Our results expand the molecular understanding of enzyme encapsulation inside protein nanocompartments and lay the foundation for rationally modulating encapsulin cargo loading for biomedical and biotechnological applications.
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Affiliation(s)
- Jesse A. Jones
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Michael P. Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Tobias W. Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
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18
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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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19
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Babar TK, Glare TR, Hampton JG, Hurst MRH, Narciso J, Sheen CR, Koch B. Linocin M18 protein from the insect pathogenic bacterium Brevibacillus laterosporus isolates. Appl Microbiol Biotechnol 2023; 107:4337-4353. [PMID: 37204448 PMCID: PMC10313851 DOI: 10.1007/s00253-023-12563-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/19/2023] [Accepted: 04/29/2023] [Indexed: 05/20/2023]
Abstract
Brevibacillus laterosporus (Bl) is a Gram-positive and spore-forming bacterium. Insect pathogenic strains have been characterised in New Zealand, and two isolates, Bl 1821L and Bl 1951, are under development for use in biopesticides. However, growth in culture is sometimes disrupted, affecting mass production. Based on previous work, it was hypothesised that Tectiviridae phages might be implicated. While investigating the cause of the disrupted growth, electron micrographs of crude lysates showed structural components of putative phages including capsid and tail-like structures. Sucrose density gradient purification yielded a putative self-killing protein of ~30 kDa. N-terminal sequencing of the ~30 kDa protein identified matches to a predicted 25 kDa hypothetical and a 31.4 kDa putative encapsulating protein homologs, with the genes encoding each protein adjacent in the genomes. BLASTp analysis of the homologs of 31.4 kDa amino acid sequences shared 98.6% amino acid identity to the Linocin M18 bacteriocin family protein of Brevibacterium sp. JNUCC-42. Bioinformatic tools including AMPA and CellPPD defined that the bactericidal potential originated from a putative encapsulating protein. Antagonistic activity of the ~30 kDa encapsulating protein of Bl 1821L and Bl 1951during growth in broth exhibited bacterial autolytic activity. LIVE/DEAD staining of Bl 1821L cells after treatment with the ~30 kDa encapsulating protein of Bl 1821L substantiated the findings by showing 58.8% cells with the compromised cell membranes as compared to 37.5% cells in the control. Furthermore, antibacterial activity of the identified proteins of Bl 1821L was validated through gene expression in a Gram-positive bacterium Bacillus subtilis WB800N. KEY POINTS: • Gene encoding the 31.4 kDa antibacterial Linocin M18 protein was identified • It defined the autocidal activity of Linocin M18 (encapsulating) protein • Identified the possible killing mechanism of the encapsulins.
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Affiliation(s)
- Tauseef K Babar
- Bio-Protection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand.
- Department of Entomology, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, 60000, Pakistan.
| | - Travis R Glare
- Bio-Protection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
| | - John G Hampton
- Bio-Protection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
| | - Mark R H Hurst
- Resilient Agriculture, AgResearch, Lincoln Research Centre, Christchurch, New Zealand
| | - Josefina Narciso
- Bio-Protection Research Centre, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, 7647, New Zealand
| | - Campbell R Sheen
- Protein Science and Engineering, Callaghan Innovation, Christchurch, New Zealand
| | - Barbara Koch
- Protein Science and Engineering, Callaghan Innovation, Christchurch, New Zealand
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20
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Abstract
Encapsulins are a recently discovered class of prokaryotic self-assembling icosahedral protein nanocompartments measuring between 24 and 42 nm in diameter, capable of selectively encapsulating dedicated cargo proteins in vivo. They have been classified into four families based on sequence identity and operon structure, and thousands of encapsulin systems have recently been computationally identified across a wide range of bacterial and archaeal phyla. Cargo encapsulation is mediated by the presence of specific targeting motifs found in all native cargo proteins that interact with the interior surface of the encapsulin shell during self-assembly. Short C-terminal targeting peptides (TPs) are well documented in Family 1 encapsulins, while more recently, larger N-terminal targeting domains (TDs) have been discovered in Family 2. The modular nature of TPs and their facile genetic fusion to non-native cargo proteins of interest has made cargo encapsulation, both in vivo and in vitro, readily exploitable and has therefore resulted in a range of rationally engineered nano-compartmentalization systems. This review summarizes current knowledge on cargo protein encapsulation within encapsulins and highlights select studies that utilize TP fusions to non-native cargo in creative and useful ways.
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Affiliation(s)
- Jesse A Jones
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Robert Benisch
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
| | - Tobias W Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, USA
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21
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Jones JA, Andreas MP, Giessen TW. Exploring the Extreme Acid Tolerance of a Dynamic Protein Nanocage. Biomacromolecules 2023; 24:1388-1399. [PMID: 36796007 DOI: 10.1021/acs.biomac.2c01424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Encapsulins are microbial protein nanocages capable of efficient self-assembly and cargo enzyme encapsulation. Due to their favorable properties, including high thermostability, protease resistance, and robust heterologous expression, encapsulins have become popular bioengineering tools for applications in medicine, catalysis, and nanotechnology. Resistance against physicochemical extremes like high temperature and low pH is a highly desirable feature for many biotechnological applications. However, no systematic search for acid-stable encapsulins has been carried out, while the influence of pH on encapsulin shells has so far not been thoroughly explored. Here, we report on a newly identified encapsulin nanocage from the acid-tolerant bacterium Acidipropionibacterium acidipropionici. Using transmission electron microscopy, dynamic light scattering, and proteolytic assays, we demonstrate its extreme acid tolerance and resilience against proteases. We structurally characterize the novel nanocage using cryo-electron microscopy, revealing a dynamic five-fold pore that displays distinct "closed" and "open" states at neutral pH but only a singular "closed" state under strongly acidic conditions. Further, the "open" state exhibits the largest pore in an encapsulin shell reported to date. Non-native protein encapsulation capabilities are demonstrated, and the influence of external pH on internalized cargo is explored. Our results expand the biotechnological application range of encapsulin nanocages toward potential uses under strongly acidic conditions and highlight pH-responsive encapsulin pore dynamics.
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Affiliation(s)
- Jesse A Jones
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0624, United States
| | - Michael P Andreas
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0624, United States
| | - Tobias W Giessen
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0624, United States
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, Michigan 48109-1382, United States
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22
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Kwon S, Giessen TW. Engineered Protein Nanocages for Concurrent RNA and Protein Packaging In Vivo. ACS Synth Biol 2022; 11:3504-3515. [PMID: 36170610 PMCID: PMC9944510 DOI: 10.1021/acssynbio.2c00391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Protein nanocages have emerged as an important engineering platform for biotechnological and biomedical applications. Among naturally occurring protein cages, encapsulin nanocompartments have recently gained prominence due to their favorable physico-chemical properties, ease of shell modification, and highly efficient and selective intrinsic protein packaging capabilities. Here, we expand encapsulin function by designing and characterizing encapsulins for concurrent RNA and protein encapsulation in vivo. Our strategy is based on modifying encapsulin shells with nucleic acid-binding peptides without disrupting the native protein packaging mechanism. We show that our engineered encapsulins reliably self-assemble in vivo, are capable of efficient size-selective in vivo RNA packaging, can simultaneously load multiple functional RNAs, and can be used for concurrent in vivo packaging of RNA and protein. Our engineered encapsulation platform has potential for codelivery of therapeutic RNAs and proteins to elicit synergistic effects and as a modular tool for other biotechnological applications.
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Affiliation(s)
- Seokmu Kwon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Tobias W. Giessen
- Department of Biological Chemistry and Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
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23
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Andreas MP, Giessen TW. Heterologous expression and purification of encapsulins in Streptomyces coelicolor. MethodsX 2022; 9:101787. [PMID: 35898614 PMCID: PMC9309400 DOI: 10.1016/j.mex.2022.101787] [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] [Received: 05/06/2022] [Accepted: 07/11/2022] [Indexed: 01/31/2023] Open
Abstract
In recent years a large number of encapsulin nanocompartment-encoding operons have been identified in bacterial and archaeal genomes. Encapsulin-encoding genes and operons from GC-rich Gram-positive bacteria, particularly of the phylum Actinobacteria, are often difficult to overexpress and purify in a soluble form using standard Escherichia coli expression systems. Here, we present a protocol to heterologously overexpress encapsulin nanocompartments and encapsulin-containing operons in Streptomyces coelicolor. Successful encapsulin production begins with the transfer of a Streptomyces expression plasmid, encoding the gene(s) of interest, via conjugation to the model actinobacterium S. coelicolor. After growing the conjugated S. coelicolor culture to the optimal optical density, protein production is induced by the addition of the inducer thiostrepton, followed by expression in liquid culture for 1-3 days. Cells are lysed and encapsulin proteins purified using ammonium sulfate precipitation and size exclusion chromatography. The method outlined in this protocol can be utilized to improve cargo loading and overall soluble expression of encapsulin systems when compared to expression in E. coli.•Clone an encapsulin-encoding gene or operon into a Streptomyces expression vector.•Transfer the Streptomyces expression vector to S. coelicolor via conjugation.•Heterologously express and purify empty or cargo-loaded encapsulins from S. coelicolor.
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Affiliation(s)
- Michael P. Andreas
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Tobias W. Giessen
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA,Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA,Corresponding author at: Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, MI, USA.
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24
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Condensation and Protection of DNA by the Myxococcus xanthus Encapsulin: A Novel Function. Int J Mol Sci 2022; 23:ijms23147829. [PMID: 35887179 PMCID: PMC9321382 DOI: 10.3390/ijms23147829] [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] [Received: 05/01/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 02/04/2023] Open
Abstract
Encapsulins are protein nanocages capable of harboring smaller proteins (cargo proteins) within their cavity. The function of the encapsulin systems is related to the encapsulated cargo proteins. The Myxococcus xanthus encapsulin (EncA) naturally encapsulates ferritin-like proteins EncB and EncC as cargo, resulting in a large iron storage nanocompartment, able to accommodate up to 30,000 iron atoms per shell. In the present manuscript we describe the binding and protection of circular double stranded DNA (pUC19) by EncA using electrophoretic mobility shift assays (EMSA), atomic force microscopy (AFM), and DNase protection assays. EncA binds pUC19 with an apparent dissociation constant of 0.3 ± 0.1 µM and a Hill coefficient of 1.4 ± 0.1, while EncC alone showed no interaction with DNA. Accordingly, the EncAC complex displayed a similar DNA binding capacity as the EncA protein. The data suggest that initially, EncA converts the plasmid DNA from a supercoiled to a more relaxed form with a beads-on-a-string morphology. At higher concentrations, EncA self-aggregates, condensing the DNA. This process physically protects DNA from enzymatic digestion by DNase I. The secondary structure and thermal stability of EncA and the EncA-pUC19 complex were evaluated using synchrotron radiation circular dichroism (SRCD) spectroscopy. The overall secondary structure of EncA is maintained upon interaction with pUC19 while the melting temperature of the protein (Tm) slightly increased from 76 ± 1 °C to 79 ± 1 °C. Our work reports, for the first time, the in vitro capacity of an encapsulin shell to interact and protect plasmid DNA similarly to other protein nanocages that may be relevant in vivo.
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25
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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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26
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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: 25] [Impact Index Per Article: 12.5] [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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27
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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: 19] [Impact Index Per Article: 9.5] [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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28
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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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29
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Jones JA, Cristie-David AS, Andreas MP, Giessen TW. Triggered Reversible Disassembly of an Engineered Protein Nanocage*. Angew Chem Int Ed Engl 2021; 60:25034-25041. [PMID: 34532937 PMCID: PMC8578439 DOI: 10.1002/anie.202110318] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Indexed: 01/13/2023]
Abstract
Protein nanocages play crucial roles in sub-cellular compartmentalization and spatial control in all domains of life and have been used as biomolecular tools for applications in biocatalysis, drug delivery, and bionanotechnology. The ability to control their assembly state under physiological conditions would further expand their practical utility. To gain such control, we introduced a peptide capable of triggering conformational change at a key structural position in the largest known encapsulin nanocompartment. We report the structure of the resulting engineered nanocage and demonstrate its ability to disassemble and reassemble on demand under physiological conditions. We demonstrate its capacity for in vivo encapsulation of proteins of choice while also demonstrating in vitro cargo loading capabilities. Our results represent a functionally robust addition to the nanocage toolbox and a novel approach for controlling protein nanocage disassembly and reassembly under mild conditions.
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Affiliation(s)
- Jesse A Jones
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, 1150 W. Medical Center Dr., MSRB2, Ann Arbor, MI, 48109-5622, USA
| | - Ajitha S Cristie-David
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, 1150 W. Medical Center Dr., MSRB2, Ann Arbor, MI, 48109-5622, USA
| | - Michael P Andreas
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, 1150 W. Medical Center Dr., MSRB2, Ann Arbor, MI, 48109-5622, USA
| | - Tobias W Giessen
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, 1150 W. Medical Center Dr., MSRB2, Ann Arbor, MI, 48109-5622, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, 1150 W. Medical Center Dr., MSRB2, Ann Arbor, MI, 48109-5622, USA
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30
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Jones JA, Cristie‐David AS, Andreas MP, Giessen TW. Triggered Reversible Disassembly of an Engineered Protein Nanocage**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jesse A. Jones
- Department of Biomedical Engineering University of Michigan Medical School, Ann Arbor 1150 W. Medical Center Dr., MSRB2 Ann Arbor MI 48109-5622 USA
| | - Ajitha S. Cristie‐David
- Department of Biomedical Engineering University of Michigan Medical School, Ann Arbor 1150 W. Medical Center Dr., MSRB2 Ann Arbor MI 48109-5622 USA
| | - Michael P. Andreas
- Department of Biomedical Engineering University of Michigan Medical School, Ann Arbor 1150 W. Medical Center Dr., MSRB2 Ann Arbor MI 48109-5622 USA
| | - Tobias W. Giessen
- Department of Biomedical Engineering University of Michigan Medical School, Ann Arbor 1150 W. Medical Center Dr., MSRB2 Ann Arbor MI 48109-5622 USA
- Department of Biological Chemistry University of Michigan Medical School, Ann Arbor 1150 W. Medical Center Dr., MSRB2 Ann Arbor MI 48109-5622 USA
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31
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Abstract
Increasing efficiency is an important driving force behind cellular organization and often achieved through compartmentalization. Long recognized as a core principle of eukaryotic cell organization, its widespread occurrence in prokaryotes has only recently come to light. Despite the early discovery of a few microcompartments such as gas vesicles and carboxysomes, the vast majority of these structures in prokaryotes are less than 100 nm in diameter - too small for conventional light microscopy and electron microscopic thin sectioning. Consequently, these smaller-sized nanocompartments have therefore been discovered serendipitously and then through bioinformatics shown to be broadly distributed. Their small uniform size, robust self-assembly, high stability, excellent biocompatibility, and large cargo capacity make them excellent candidates for biotechnology applications. This review will highlight our current knowledge of nanocompartments, the prospects for applications as well as open question and challenges that need to be addressed to fully understand these important structures.
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