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Swanson J, Navarrette A, Knox J, Kim H, Stanley F. Microbial Influence on the Mobility of +3 Actinides from a Salt-Based Nuclear Waste Repository. Microorganisms 2023; 11:1370. [PMID: 37374872 DOI: 10.3390/microorganisms11061370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/29/2023] Open
Abstract
Biologically enhanced transport of radionuclides is one of several processes that can affect the performance of a nuclear waste repository. In this work, several microbial isolates from the Waste Isolation Pilot Plant (WIPP) were tested for their influence on the concentration of neodymium, as an analog for +3 actinides, in simple sodium chloride solutions and in anoxic WIPP brines. Batch sorption experiments were carried out over a period of 4-5 weeks. In many cases, the effect on neodymium in solution was immediate and extensive and assumed to be due to surface complexation. However, over time, the continued loss of Nd from the solution was more likely due to biologically induced precipitation and/or mineralization and possible entrapment in extracellular polymeric substances. The results showed no correlation between organism type and the extent of its influence on neodymium in solution. However, a correlation was observed between different test matrices (simple NaCl versus high-magnesium brine versus high-NaCl brine). Further experiments were conducted to test these matrix effects, and the results showed a significant effect of magnesium concentration on the ability of microorganisms to remove Nd from solution. Possible mechanisms include cation competition and the alteration of cell surface structures. This suggests that the aqueous chemistry of the WIPP environs could play a larger role in the final disposition of +3 actinides than the microbiology.
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Affiliation(s)
- Julie Swanson
- Los Alamos National Laboratory, Carlsbad, NM 88220, USA
| | | | - Jandi Knox
- Los Alamos National Laboratory, Carlsbad, NM 88220, USA
| | - Hannah Kim
- Los Alamos National Laboratory, Carlsbad, NM 88220, USA
| | - Floyd Stanley
- Los Alamos National Laboratory, Carlsbad, NM 88220, USA
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2
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Fioravanti A, Mathelie-Guinlet M, Dufrêne YF, Remaut H. The Bacillus anthracis S-layer is an exoskeleton-like structure that imparts mechanical and osmotic stabilization to the cell wall. PNAS NEXUS 2022; 1:pgac121. [PMID: 36714836 PMCID: PMC9802277 DOI: 10.1093/pnasnexus/pgac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 08/02/2022] [Indexed: 02/05/2023]
Abstract
Surface layers (S-layers) are 2D paracrystalline protein monolayers covering the cell envelope of many prokaryotes and archaea. Proposed functions include a role in cell support, as scaffolding structure, as molecular sieve, or as virulence factor. Bacillus anthracis holds two S-layers, composed of Sap or EA1, which interchange in early and late exponential growth phase. We previously found that acute disruption of B. anthracis Sap S-layer integrity, by means of nanobodies, results in severe morphological cell surface defects and cell collapse. Remarkably, this loss of function is due to the destruction of the Sap lattice structure rather than detachment of monomers from the cell surface. Here, we combine force nanoscopy and light microscopy observations to probe the contribution of the S-layer to the mechanical, structural, and functional properties of the cell envelope, which have been so far elusive. Our experiments reveal that cells with a compromised S-layer lattice show a decreased compressive stiffness and elastic modulus. Furthermore, we find that S-layer integrity is required to resist cell turgor under hypotonic conditions. These results present compelling experimental evidence indicating that the S-layers can serve as prokaryotic exoskeletons that support the cell wall in conferring rigidity and mechanical stability to bacterial cells.
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Affiliation(s)
- Antonella Fioravanti
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Marion Mathelie-Guinlet
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Yves F Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Han Remaut
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050 Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
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3
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Herdman M, von Kügelgen A, Kureisaite-Ciziene D, Duman R, El Omari K, Garman EF, Kjaer A, Kolokouris D, Löwe J, Wagner A, Stansfeld PJ, Bharat TAM. High-resolution mapping of metal ions reveals principles of surface layer assembly in Caulobacter crescentus cells. Structure 2021; 30:215-228.e5. [PMID: 34800371 PMCID: PMC8828063 DOI: 10.1016/j.str.2021.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/17/2021] [Accepted: 10/22/2021] [Indexed: 12/02/2022]
Abstract
Surface layers (S-layers) are proteinaceous crystalline coats that constitute the outermost component of most prokaryotic cell envelopes. In this study, we have investigated the role of metal ions in the formation of the Caulobacter crescentus S-layer using high-resolution structural and cell biology techniques, as well as molecular simulations. Utilizing optical microscopy of fluorescently tagged S-layers, we show that calcium ions facilitate S-layer lattice formation and cell-surface binding. We report all-atom molecular dynamics simulations of the S-layer lattice, revealing the importance of bound metal ions. Finally, using electron cryomicroscopy and long-wavelength X-ray diffraction experiments, we mapped the positions of metal ions in the S-layer at near-atomic resolution, supporting our insights from the cellular and simulations data. Our findings contribute to the understanding of how C. crescentus cells form a regularly arranged S-layer on their surface, with implications on fundamental S-layer biology and the synthetic biology of self-assembling biomaterials. Live imaging shows Ca2+-dependent expansion of the C. crescentus S-layer Molecular simulations reveal Ca2+-binding properties of the S-layer Ca2+ ion mapping in three-dimensional crystals using in-vacuum X-ray anomalous diffraction Ca2+ replacement by Ho3+ allows cryo-EM mapping of heavy metals
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Affiliation(s)
- Matthew Herdman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | | | | | - Ramona Duman
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Kamel El Omari
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Elspeth F Garman
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Andreas Kjaer
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Jan Löwe
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Armin Wagner
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot OX11 0DE, UK
| | - Phillip J Stansfeld
- School of Life Sciences and Department of Chemistry, Gibbet Hill Campus, University of Warwick, Coventry CV4 7AL, UK.
| | - Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
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4
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Ali S, Jenkins B, Cheng J, Lobb B, Wei X, Egan S, Charles TC, McConkey BJ, Austin J, Doxey AC. Slr4, a newly identified S-layer protein from marine Gammaproteobacteria, is a major biofilm matrix component. Mol Microbiol 2020; 114:979-990. [PMID: 32804439 PMCID: PMC7821379 DOI: 10.1111/mmi.14588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/06/2020] [Indexed: 01/03/2023]
Abstract
S‐layers are paracrystalline proteinaceous lattices that surround prokaryotic cells, forming a critical interface between the cells and their extracellular environment. Here, we report the discovery of a novel S‐layer protein present in the Gram‐negative marine organism, Pseudoalteromonas tunicata D2. An uncharacterized protein (EAR28894) was identified as the most abundant protein in planktonic cultures and biofilms. Bioinformatic methods predicted a beta‐helical structure for EAR28894 similar to the Caulobacter S‐layer protein, RsaA, despite sharing less than 20% sequence identity. Transmission electron microscopy revealed that purified EAR28894 protein assembled into paracrystalline sheets with a unique square lattice symmetry and a unit cell spacing of ~9.1 nm. An S‐layer was found surrounding the outer membrane in wild‐type cells and completely removed from cells in an EAR28894 deletion mutant. S‐layer material also appeared to be “shed” from wild‐type cells and was highly abundant in the extracellular matrix where it is associated with outer membrane vesicles and other matrix components. EAR28894 and its homologs form a new family of S‐layer proteins that are widely distributed in Gammaproteobacteria including species of Pseudoalteromonas and Vibrio, and found exclusively in marine metagenomes. We propose the name Slr4 for this novel protein family.
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Affiliation(s)
- Sura Ali
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Benjamin Jenkins
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Jiujun Cheng
- Department of Biology, University of Waterloo, Waterloo, ON, Canada.,Metagenom Bio Life Science Inc., Waterloo, ON, Canada
| | - Briallen Lobb
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Xin Wei
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Suhelen Egan
- Centre for Marine Science and Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales Sydney, Sydney, NSW, Australia
| | - Trevor C Charles
- Department of Biology, University of Waterloo, Waterloo, ON, Canada.,Metagenom Bio Life Science Inc., Waterloo, ON, Canada
| | | | - John Austin
- Bureau of Microbial Hazards, Health Products and Food Branch, Health Canada, Ottawa, ON, Canada
| | - Andrew C Doxey
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Simonin P, Lombard C, Huguet A, Kish A. Improved Isolation of SlaA and SlaB S-layer proteins in Sulfolobus acidocaldarius. Extremophiles 2020; 24:673-680. [PMID: 32494965 DOI: 10.1007/s00792-020-01179-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/15/2020] [Indexed: 01/19/2023]
Abstract
The Sulfolobus acidocaldarius S-layer is composed of two main proteins: SlaA, which forms the ordered structure of the S-layer matrix, and SlaB, which supports and anchors the S-layer into the tetraether lipid membrane. While SlaA has previously been purified by exploiting its thermotolerance and high resistance to detergents, SlaB has resisted isolation, particularly from the cell membrane. Removal of proteins other than those of the S-layer is especially difficult if large batch-scale culture volumes are unavailable. Here, we describe a benchtop-scale protocol for the purification of SlaA from S. acidocaldarius, enabling isolation of SlaB using size exclusion chromatography (gel filtration). Using this protocol, we were able to identify for the first time tetraether lipids strongly attached to SlaB via heat- and detergent-resistant interactions.
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Affiliation(s)
- Pierre Simonin
- Molécules de Communication et Adaptation des Microorganismes (MCAM), Muséum national d'Histoire naturelle, CNRS, CP 54, 57 rue Cuvier, 75005, Paris, France
| | - Carine Lombard
- Molécules de Communication et Adaptation des Microorganismes (MCAM), Muséum national d'Histoire naturelle, CNRS, CP 54, 57 rue Cuvier, 75005, Paris, France
| | - Arnaud Huguet
- Sorbonne Université, CNRS, École Pratique des Hautes Études, UMR 7619 METIS, 4, place Jussieu, 75005, Paris, France
| | - Adrienne Kish
- Molécules de Communication et Adaptation des Microorganismes (MCAM), Muséum national d'Histoire naturelle, CNRS, CP 54, 57 rue Cuvier, 75005, Paris, France.
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