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Zhou Y, Yan A, Yang J, He W, Guo S, Li Y, Wu J, Dai Y, Pan X, Cui D, Pereira O, Teng W, Bi R, Chen S, Fan L, Wang P, Liao Y, Qin W, Sui SF, Zhu Y, Zhang C, Liu Z. Ultrastructural insights into cellular organization, energy storage and ribosomal dynamics of an ammonia-oxidizing archaeon from oligotrophic oceans. Front Microbiol 2024; 15:1367658. [PMID: 38737410 PMCID: PMC11082331 DOI: 10.3389/fmicb.2024.1367658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/16/2024] [Indexed: 05/14/2024] Open
Abstract
Introduction Nitrososphaeria, formerly known as Thaumarchaeota, constitute a diverse and widespread group of ammonia-oxidizing archaea (AOA) inhabiting ubiquitously in marine and terrestrial environments, playing a pivotal role in global nitrogen cycling. Despite their importance in Earth's ecosystems, the cellular organization of AOA remains largely unexplored, leading to a significant unanswered question of how the machinery of these organisms underpins metabolic functions. Methods In this study, we combined spherical-chromatic-aberration-corrected cryo-electron tomography (cryo-ET), scanning transmission electron microscopy (STEM), and energy dispersive X-ray spectroscopy (EDS) to unveil the cellular organization and elemental composition of Nitrosopumilus maritimus SCM1, a representative member of marine Nitrososphaeria. Results and Discussion Our tomograms show the native ultrastructural morphology of SCM1 and one to several dense storage granules in the cytoplasm. STEM-EDS analysis identifies two types of storage granules: one type is possibly composed of polyphosphate and the other polyhydroxyalkanoate. With precise measurements using cryo-ET, we observed low quantity and density of ribosomes in SCM1 cells, which are in alignment with the documented slow growth of AOA in laboratory cultures. Collectively, these findings provide visual evidence supporting the resilience of AOA in the vast oligotrophic marine environment.
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Affiliation(s)
- Yangkai Zhou
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - An Yan
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jiawen Yang
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Wei He
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Shuai Guo
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yifan Li
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Jing Wu
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yanchao Dai
- Shanghai NanoPort, Thermo Fisher Scientific Inc., Shanghai, China
| | - Xijiang Pan
- Shanghai NanoPort, Thermo Fisher Scientific Inc., Shanghai, China
| | - Dongyu Cui
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Olivier Pereira
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Institut AMU-WUT, Aix-Marseille Université and Wuhan University of Technology, Wuhan, Hubei, China
| | - Wenkai Teng
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Ran Bi
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Songze Chen
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lu Fan
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Peiyi Wang
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yan Liao
- Australian Institute for Microbiology & Infection, University of Technology Sydney, Ultimo, NSW, Australia
| | - Wei Qin
- School of Biological Sciences and Institute for Environmental Genomics, University of Oklahoma, Norman, OK, United States
| | - Sen-Fang Sui
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuanqing Zhu
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Shanghai Sheshan National Geophysical Observatory, Shanghai, China
| | - Chuanlun Zhang
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
- Shanghai Sheshan National Geophysical Observatory, Shanghai, China
- Advanced Institute for Ocean Research, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Zheng Liu
- Cryo-Electron Microscopy Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
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Blackholly LR, Harris NJ, Findlay HE, Booth PJ. Cell-Free Expression to Probe Co-Translational Insertion of an Alpha Helical Membrane Protein. Front Mol Biosci 2022; 9:795212. [PMID: 35187078 PMCID: PMC8847741 DOI: 10.3389/fmolb.2022.795212] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/11/2022] [Indexed: 01/23/2023] Open
Abstract
The majority of alpha helical membrane proteins fold co-translationally during their synthesis on the ribosome. In contrast, most mechanistic folding studies address refolding of full-length proteins from artificially induced denatured states that are far removed from the natural co-translational process. Cell-free translation of membrane proteins is emerging as a useful tool to address folding during translation by a ribosome. We summarise the benefits of this approach and show how it can be successfully extended to a membrane protein with a complex topology. The bacterial leucine transporter, LeuT can be synthesised and inserted into lipid membranes using a variety of in vitro transcription translation systems. Unlike major facilitator superfamily transporters, where changes in lipids can optimise the amount of correctly inserted protein, LeuT insertion yields are much less dependent on the lipid composition. The presence of a bacterial translocon either in native membrane extracts or in reconstituted membranes also has little influence on the yield of LeuT incorporated into the lipid membrane, except at high reconstitution concentrations. LeuT is considered a paradigm for neurotransmitter transporters and possesses a knotted structure that is characteristic of this transporter family. This work provides a method in which to probe the formation of a protein as the polypeptide chain is being synthesised on a ribosome and inserting into lipids. We show that in comparison with the simpler major facilitator transporter structures, LeuT inserts less efficiently into membranes when synthesised cell-free, suggesting that more of the protein aggregates, likely as a result of the challenging formation of the knotted topology in the membrane.
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Affiliation(s)
| | | | | | - Paula J. Booth
- Department of Chemistry, King’s College London, London, United Kingdom
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Bollschweiler D, Schaffer M, Lawrence CM, Engelhardt H. Cryo-electron microscopy of an extremely halophilic microbe: technical aspects. Extremophiles 2017; 21:393-398. [PMID: 28050645 PMCID: PMC5329092 DOI: 10.1007/s00792-016-0912-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/19/2016] [Indexed: 11/30/2022]
Abstract
Most halophilic Archaea of the class Halobacteriaceae depend on the presence of several molar sodium chloride for growth and cell integrity. This poses problems for structural studies, particularly for electron microscopy, where the high salt concentration results in diminished contrast. Since cryo-electron microscopy of intact cells provides new insights into the cellular and molecular organization under close-to-live conditions, we evaluated strategies and conditions to make halophilic microbes available for investigations in situ. Halobacterium salinarum, the test organism for this study, usually grows at 4.3 M NaCl. Adaptation to lower concentrations and subsequent NaCl reduction via dialysis led to still vital cells at 3 M salt. A comprehensive evaluation of vitrification parameters, thinning of frozen cells by focused-ion-beam micromachining, and cryo-electron microscopy revealed that structural studies under high salt conditions are possible in situ.
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Affiliation(s)
- Daniel Bollschweiler
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Miroslava Schaffer
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - C Martin Lawrence
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Harald Engelhardt
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany.
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Kwan DC, Thomas JR, Bolhuis A. Bioenergetic requirements of a Tat-dependent substrate in the halophilic archaeon Haloarcula hispanica. FEBS J 2008; 275:6159-67. [PMID: 19016855 DOI: 10.1111/j.1742-4658.2008.06740.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Twin-arginine translocase (Tat) is involved in the translocation of fully folded proteins in a process that is driven by the proton motive force. In most prokaryotes, the Tat system transports only a small proportion of secretory proteins, and Tat substrates are often cofactor-containing proteins that require folding before translocation. A notable exception is found in halophilic archaea (haloarchaea), which are predicted to secrete the majority of their proteins through the Tat pathway. In this study, we have analysed the translocation of a secretory protein (AmyH) from the haloarchaeon Haloarcula hispanica. Using both in vivo and in vitro translocation assays, we demonstrate that AmyH transport is Tat-dependent, and, surprisingly, that its secretion does not depend on the proton motive force but requires the sodium motive force instead.
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Affiliation(s)
- Daniel C Kwan
- Department of Pharmacy and Pharmacology, University of Bath, UK
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Higuchi ML, Santos MH, Roggério A, Kawakami JT, Bezerra HG, Canzian M. A role for archaeal organisms in development of atherosclerotic vulnerable plaques and myxoid matrices. Clinics (Sao Paulo) 2006; 61:473-8. [PMID: 17072447 DOI: 10.1590/s1807-59322006000500016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 08/07/2006] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Vulnerable plaques are characterized by a myxoid matrix, necrotic lipidic core, reactive oxygen species, and high levels of microorganisms. Aerobic microbes such as Chlamydophila pneumoniae and Mycoplasma pneumoniae usually do not survive in oxidative stress media. Archaea are anaerobic microbes with powerful anti-oxidative enzymes that allow detoxification of free radicals whose presence might favor the survival of aerobic microorganisms. We searched for archaeal organisms in vulnerable plaques, and possible associations with myxoid matrix, chlamydia, and mycoplasma bodies. METHODS Twenty-nine tissue samples from 13 coronary artherectomies from large excentric ostial or bifurcational lesions were studied using optical and electron microscopy. Infectious agents compatible with archaea, chlamydia, and mycoplasma were semiquantified using electron micrographs and correlated with the amounts of fibromuscular tissue, myxoid matrix, and foam cells, as determined from semi-thin sections. Six of the cases were also submitted to polymerase chain reaction with archaeal primers. RESULTS All 13 specimens showed archaeal-compatible structures and chlamydial and mycoplasmal bodies in at least 1 sample. There was a positive correlation between extent of the of myxoid matrix and archaeal bodies (r = 0.44, P = 0.02); between archaeal and mycoplasmal bodies (r = 0.41, P = 0.03), and between chlamydial bodies and foam cells (r = 0.42; P = 0.03). The PCR test was positive for archaeal DNA in 4 of the 6 fragments. DISCUSSION DNA and forms suggestive of archaea are present in vulnerable plaques and may have a fundamental role in the proliferation of mycoplasma and chlamydia. This seems to be the first description of apparently pathogenic archaea in human internal organ lesions.
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Affiliation(s)
- Maria L Higuchi
- Heart Institute, Hospital das Clínicas, São Paulo University Medical School, São Paulo, SP, Brazil
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Lichi T, Ring G, Eichler J. Membrane binding of SRP pathway components in the halophilic archaea Haloferax volcanii. ACTA ACUST UNITED AC 2004; 271:1382-90. [PMID: 15030489 DOI: 10.1111/j.1432-1033.2004.04050.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Across evolution, the signal recognition particle pathway targets extra-cytoplasmic proteins to membranous translocation sites. Whereas the pathway has been extensively studied in Eukarya and Bacteria, little is known of this system in Archaea. In the following, membrane association of FtsY, the prokaryal signal recognition particle receptor, and SRP54, a central component of the signal recognition particle, was addressed in the halophilic archaea Haloferax volcanii. Purified H. volcanii FtsY, the FtsY C-terminal GTP-binding domain (NG domain) or SRP54, were combined separately or in different combinations with H. volcanii inverted membrane vesicles and examined by gradient floatation to differentiate between soluble and membrane-bound protein. Such studies revealed that both FtsY and the FtsY NG domain bound to H. volcanii vesicles in a manner unaffected by proteolytic pretreatment of the membranes, implying that in Archaea, FtsY association is mediated through the membrane lipids. Indeed, membrane association of FtsY was also detected in intact H. volcanii cells. The contribution of the NG domain to FtsY binding in halophilic archaea may be considerable, given the low number of basic charges found at the start of the N-terminal acidic domain of haloarchaeal FtsY proteins (the region of the protein thought to mediate FtsY-membrane association in Bacteria). Moreover, FtsY, but not the NG domain, was shown to mediate membrane association of H. volcanii SRP54, a protein that did not otherwise interact with the membrane.
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Affiliation(s)
- Tovit Lichi
- Department of Life Sciences, Ben Gurion University of the Negev, Beersheva, Israel
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Tozik I, Huang Q, Zwieb C, Eichler J. Reconstitution of the signal recognition particle of the halophilic archaeon Haloferax volcanii. Nucleic Acids Res 2002; 30:4166-75. [PMID: 12364595 PMCID: PMC140548 DOI: 10.1093/nar/gkf548] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The signal recognition particle (SRP) is a ribonucleoprotein complex involved in the recognition and targeting of nascent extracytoplasmic proteins in all three domains of life. In Archaea, SRP contains 7S RNA like its eukaryal counterpart, yet only includes two of the six protein subunits found in the eukaryal complex. To further our understanding of the archaeal SRP, 7S RNA, SRP19 and SRP54 of the halophilic archaeon Haloferax volcanii have been expressed and purified, and used to reconstitute the ternary SRP complex. The availability of SRP components from a haloarchaeon offers insight into the structure, assembly and function of this ribonucleoprotein complex at saturating salt conditions. While the amino acid sequences of H.volcanii SRP19 and SRP54 are modified presumably as an adaptation to their saline surroundings, the interactions between these halophilic SRP components and SRP RNA appear conserved, with the possibility of a few exceptions. Indeed, the H.volcanii SRP can assemble in the absence of high salt. As reported with other archaeal SRPs, the limited binding of H.volcanii SRP54 to SRP RNA is enhanced in the presence of SRP19. Finally, immunolocalization reveals that H.volcanii SRP54 is found in the cytosolic fraction, where it is associated with the ribosomal fraction of the cell.
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Affiliation(s)
- Irit Tozik
- Department of Life Sciences, Ben Gurion University of the Negev, PO Box 653, Beersheva 84105, Israel
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