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Zhou J, Dong L. Structural insights linking H-bridging of archaeal GDGTs to high temperature. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:174120. [PMID: 38901598 DOI: 10.1016/j.scitotenv.2024.174120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/22/2024]
Abstract
Isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs), characteristic membrane lipids of archaea, are widely used in ecological and geochemical studies, especially for paleoenvironmental reconstruction. Glycerol monoalkyl glycerol tetraethers (GMGTs, also known as H-GDGTs), a unique variant of GDGTs, have covalent bonds linking the two alkyl chains. Despite some studies suggesting a link between GMGTs and high temperatures, the reliability and mechanisms remain unclear. Using molecular dynamics simulations, we elucidated the mechanism connecting GMGTs to high temperatures. Our findings show that H-bridging linkages reduce the distance between alkyl chains, leading to thicker and denser membranes with lower fluidity and permeability. The diffusion coefficient of GMGTs decreased by approximately 35 % compared to GDGTs, indicating their role as a archaeal high-temperature adaptation. This study provides a mechanistic basis for using archaeal GMGTs in geochemical studies and enhances confidence in their use for paleotemperature reconstruction.
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Affiliation(s)
- Jiaming Zhou
- Key Laboratory of Polar Ecosystem and Climate Change, Ministry of Education; and School of Oceanography, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China
| | - Liang Dong
- Key Laboratory of Polar Ecosystem and Climate Change, Ministry of Education; and School of Oceanography, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030, China.
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2
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Cui K, Wang Y, Zhang X, Zhang X, Zhang X, Li Y, Shi W, Xie X. Archaeal communities change responding to anthropogenic and natural treatments of freeze-thawed soils. ENVIRONMENTAL RESEARCH 2024; 255:119150. [PMID: 38763282 DOI: 10.1016/j.envres.2024.119150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
The coverage of accumulated snow plays a significant role in inducing changes in both microbial activity and environmental factors within freeze-thaw soil systems. This study aimed to analyze the impact of snow cover on the dynamics of archeal communities in freeze-thaw soil. Furthermore, it seeks to investigate the role of fertilization in freeze-thaw soil. Four treatments were established based on snow cover and fertilization:No snow and no fertilizer (CK-N), snow cover without fertilizer (X-N), fertilizer without snow cover (T-N), and both fertilizer and snow cover (T-X). The research findings indicated that after snow cover treatment, the carbon, nitrogen, and phosphorus content in freeze-thaw soil exhibit periodic fluctuations. Snow covered effectively altered the community composition of bacteria and archaea in the soil, with a greater impact on archaeal communities than on bacterial communities. Snow covered improves the stability of archaeal communities in freeze-thaw soil. Additionally, the arrival of snow also enhanced the correlation between archaea and environmental factors, with the key archaeal phyla involved being Nanoarchaeota and Crenarchaeota. Further research showed that the application of organic fertilizers also had some impact on freeze-thaw soil, but this impact was smaller compared to snow cover. In summary, the arrival of snow could alter the archaeal community and protect nutrient elements in freeze-thaw soil, reducing their loss, and its effect is more pronounced compared to the application of organic fertilizers.
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Affiliation(s)
- Kunxue Cui
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Yumeng Wang
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Xiaoxu Zhang
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Xu Zhang
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China.
| | - Xinlin Zhang
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Yu Li
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Wenjing Shi
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
| | - Xinyu Xie
- College of Life Science, Northeast Agricultural University, Harbin, 150030, China
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Garcia AA, Chadwick GL, Liu XL, Welander PV. Identification of two archaeal GDGT lipid-modifying proteins reveals diverse microbes capable of GMGT biosynthesis and modification. Proc Natl Acad Sci U S A 2024; 121:e2318761121. [PMID: 38885389 PMCID: PMC11214058 DOI: 10.1073/pnas.2318761121] [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: 10/26/2023] [Accepted: 05/15/2024] [Indexed: 06/20/2024] Open
Abstract
Archaea produce unique membrane-spanning lipids (MSLs), termed glycerol dialkyl glycerol tetraethers (GDGTs), which aid in adaptive responses to various environmental challenges. GDGTs can be modified through cyclization, cross-linking, methylation, hydroxylation, and desaturation, resulting in structurally distinct GDGT lipids. Here, we report the identification of radical SAM proteins responsible for two of these modifications-a glycerol monoalkyl glycerol tetraether (GMGT) synthase (Gms), responsible for covalently cross-linking the two hydrocarbon tails of a GDGT to produce GMGTs, and a GMGT methylase (Gmm), capable of methylating the core hydrocarbon tail. Heterologous expression of Gms proteins from various archaea in Thermococcus kodakarensis results in the production of GMGTs in two isomeric forms. Further, coexpression of Gms and Gmm produces mono- and dimethylated GMGTs and minor amounts of trimethylated GMGTs with only trace GDGT methylation. Phylogenetic analyses reveal the presence of Gms homologs in diverse archaeal genomes spanning all four archaeal superphyla and in multiple bacterial phyla with the genetic potential to synthesize fatty acid-based MSLs, demonstrating that GMGT production may be more widespread than previously appreciated. We demonstrate GMGT production in three Gms-encoding archaea, identifying an increase in GMGTs in response to elevated temperature in two Archaeoglobus species and the production of GMGTs with up to six rings in Vulcanisaeta distributa. The occurrence of such highly cyclized GMGTs has been limited to environmental samples and their detection in culture demonstrates the utility of combining genetic, bioinformatic, and lipid analyses to identify producers of distinct archaeal membrane lipids.
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Affiliation(s)
- Andy A. Garcia
- Department of Earth System Science, Stanford University, Stanford, CA94305
| | - Grayson L. Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Xiao-Lei Liu
- Department of Geology and Geophysics, University of Oklahoma, Norman, OK73019
| | - Paula V. Welander
- Department of Earth System Science, Stanford University, Stanford, CA94305
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Rao A, Driessen AJM. Unraveling the multiplicity of geranylgeranyl reductases in Archaea: potential roles in saturation of terpenoids. Extremophiles 2024; 28:14. [PMID: 38280122 PMCID: PMC10821996 DOI: 10.1007/s00792-023-01330-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/15/2023] [Indexed: 01/29/2024]
Abstract
The enzymology of the key steps in the archaeal phospholipid biosynthetic pathway has been elucidated in recent years. In contrast, the complete biosynthetic pathways for proposed membrane regulators consisting of polyterpenes, such as carotenoids, respiratory quinones, and polyprenols remain unknown. Notably, the multiplicity of geranylgeranyl reductases (GGRs) in archaeal genomes has been correlated with the saturation of polyterpenes. Although GGRs, which are responsible for saturation of the isoprene chains of phospholipids, have been identified and studied in detail, there is little information regarding the structure and function of the paralogs. Here, we discuss the diversity of archaeal membrane-associated polyterpenes which is correlated with the genomic loci, structural and sequence-based analyses of GGR paralogs.
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Affiliation(s)
- Alka Rao
- Department of Molecular Microbiology, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands.
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Chiu BK, Waldbauer J, Elling FJ, Mete ÖZ, Zhang L, Pearson A, Eggleston EM, Leavitt WD. Membrane lipid and expression responses of Saccharolobus islandicus REY15A to acid and cold stress. Front Microbiol 2023; 14:1219779. [PMID: 37649629 PMCID: PMC10465181 DOI: 10.3389/fmicb.2023.1219779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/24/2023] [Indexed: 09/01/2023] Open
Abstract
Archaea adjust the number of cyclopentane rings in their glycerol dibiphytanyl glycerol tetraether (GDGT) membrane lipids as a homeostatic response to environmental stressors such as temperature, pH, and energy availability shifts. However, archaeal expression patterns that correspond with changes in GDGT composition are less understood. Here we characterize the acid and cold stress responses of the thermoacidophilic crenarchaeon Saccharolobus islandicus REY15A using growth rates, core GDGT lipid profiles, transcriptomics and proteomics. We show that both stressors result in impaired growth, lower average GDGT cyclization, and differences in gene and protein expression. Transcription data revealed differential expression of the GDGT ring synthase grsB in response to both acid stress and cold stress. Although the GDGT ring synthase encoded by grsB forms highly cyclized GDGTs with ≥5 ring moieties, S. islandicus grsB upregulation under acidic pH conditions did not correspond with increased abundances of highly cyclized GDGTs. Our observations highlight the inability to predict GDGT changes from transcription data alone. Broader analysis of transcriptomic data revealed that S. islandicus differentially expresses many of the same transcripts in response to both acid and cold stress. These included upregulation of several biosynthetic pathways and downregulation of oxidative phosphorylation and motility. Transcript responses specific to either of the two stressors tested here included upregulation of genes related to proton pumping and molecular turnover in acid stress conditions and upregulation of transposases in cold stress conditions. Overall, our study provides a comprehensive understanding of the GDGT modifications and differential expression characteristic of the acid stress and cold stress responses in S. islandicus.
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Affiliation(s)
- Beverly K. Chiu
- Department of Earth Sciences, Dartmouth College, Hanover, NH, United States
| | - Jacob Waldbauer
- Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, United States
| | - Felix J. Elling
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States
- Leibniz-Laboratory for Radiometric Dating and Isotope Research, Kiel University, Kiel, Germany
| | - Öykü Z. Mete
- Department of Earth Sciences, Dartmouth College, Hanover, NH, United States
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States
| | - Lichun Zhang
- Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, United States
| | - Ann Pearson
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States
| | - Erin M. Eggleston
- Department of Biology, Middlebury College, Middlebury, VT, United States
| | - William D. Leavitt
- Department of Earth Sciences, Dartmouth College, Hanover, NH, United States
- Department of Chemistry, Dartmouth College, Hanover, NH, United States
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Rao A, de Kok NAW, Driessen AJM. Membrane Adaptations and Cellular Responses of Sulfolobus acidocaldarius to the Allylamine Terbinafine. Int J Mol Sci 2023; 24:ijms24087328. [PMID: 37108491 PMCID: PMC10138448 DOI: 10.3390/ijms24087328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Cellular membranes are essential for compartmentalization, maintenance of permeability, and fluidity in all three domains of life. Archaea belong to the third domain of life and have a distinct phospholipid composition. Membrane lipids of archaea are ether-linked molecules, specifically bilayer-forming dialkyl glycerol diethers (DGDs) and monolayer-forming glycerol dialkyl glycerol tetraethers (GDGTs). The antifungal allylamine terbinafine has been proposed as an inhibitor of GDGT biosynthesis in archaea based on radiolabel incorporation studies. The exact target(s) and mechanism of action of terbinafine in archaea remain elusive. Sulfolobus acidocaldarius is a strictly aerobic crenarchaeon thriving in a thermoacidophilic environment, and its membrane is dominated by GDGTs. Here, we comprehensively analyzed the lipidome and transcriptome of S. acidocaldarius in the presence of terbinafine. Depletion of GDGTs and the accompanying accumulation of DGDs upon treatment with terbinafine were growth phase-dependent. Additionally, a major shift in the saturation of caldariellaquinones was observed, which resulted in the accumulation of unsaturated molecules. Transcriptomic data indicated that terbinafine has a multitude of effects, including significant differential expression of genes in the respiratory complex, motility, cell envelope, fatty acid metabolism, and GDGT cyclization. Combined, these findings suggest that the response of S. acidocaldarius to terbinafine inhibition involves respiratory stress and the differential expression of genes involved in isoprenoid biosynthesis and saturation.
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Affiliation(s)
- Alka Rao
- Department of Molecular Microbiology, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Niels A W de Kok
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy, University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Arnold J M Driessen
- Department of Molecular Microbiology, Groningen Biomolecular Science and Biotechnology Institute, University of Groningen, 9747 AG Groningen, The Netherlands
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