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Edholm F, Nandy A, Reinhardt CR, Kastner DW, Kulik HJ. Protein3D: Enabling analysis and extraction of metal-containing sites from the Protein Data Bank with molSimplify. J Comput Chem 2024; 45:352-361. [PMID: 37873926 DOI: 10.1002/jcc.27242] [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: 08/09/2023] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 10/25/2023]
Abstract
Metalloenzymes catalyze a wide range of chemical transformations, with the active site residues playing a key role in modulating chemical reactivity and selectivity. Unlike smaller synthetic catalysts, a metalloenzyme active site is embedded in a larger protein, which makes interrogation of electronic properties and geometric features with quantum mechanical calculations challenging. Here we implement the ability to fetch crystallographic structures from the Protein Data Bank and analyze the metal binding sites in the program molSimplify. We show the usefulness of the newly created protein3D class to extract the local environment around non-heme iron enzymes containing a two histidine motif and prepare 372 structures for quantum mechanical calculations. Our implementation of protein3D serves to expand the range of systems molSimplify can be used to analyze and will enable high-throughput study of metal-containing active sites in proteins.
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Affiliation(s)
- Freya Edholm
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Aditya Nandy
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Clorice R Reinhardt
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - David W Kastner
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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2
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Rhim JH, Zhou A, Amenabar MJ, Boyer GM, Elling FJ, Weber Y, Pearson A, Boyd ES, Leavitt WD. Mode of carbon and energy metabolism shifts lipid composition in the thermoacidophile Acidianus. Appl Environ Microbiol 2024; 90:e0136923. [PMID: 38236067 PMCID: PMC10880624 DOI: 10.1128/aem.01369-23] [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: 08/09/2023] [Accepted: 12/01/2023] [Indexed: 01/19/2024] Open
Abstract
The degree of cyclization, or ring index (RI), in archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids was long thought to reflect homeoviscous adaptation to temperature. However, more recent experiments show that other factors (e.g., pH, growth phase, and energy flux) can also affect membrane composition. The main objective of this study was to investigate the effect of carbon and energy metabolism on membrane cyclization. To do so, we cultivated Acidianus sp. DS80, a metabolically flexible and thermoacidophilic archaeon, on different electron donor, acceptor, and carbon source combinations (S0/Fe3+/CO2, H2/Fe3+/CO2, H2/S0/CO2, or H2/S0/glucose). We show that differences in energy and carbon metabolism can result in over a full unit of change in RI in the thermoacidophile Acidianus sp. DS80. The patterns in RI correlated with the normalized electron transfer rate between the electron donor and acceptor and did not always align with thermodynamic predictions of energy yield. In light of this, we discuss other factors that may affect the kinetics of cellular energy metabolism: electron transfer chain (ETC) efficiency, location of ETC reaction components (cytoplasmic vs. extracellular), and the physical state of electron donors and acceptors (gas vs. solid). Furthermore, the assimilation of a more reduced form of carbon during heterotrophy appears to decrease the demand for reducing equivalents during lipid biosynthesis, resulting in lower RI. Together, these results point to the fundamental role of the cellular energy state in dictating GDGT cyclization, with those cells experiencing greater energy limitation synthesizing more cyclized GDGTs.IMPORTANCESome archaea make unique membrane-spanning lipids with different numbers of five- or six-membered rings in the core structure, which modulate membrane fluidity and permeability. Changes in membrane core lipid composition reflect the fundamental adaptation strategies of archaea in response to stress, but multiple environmental and physiological factors may affect the needs for membrane fluidity and permeability. In this study, we tested how Acidianus sp. DS80 changed its core lipid composition when grown with different electron donor/acceptor pairs. We show that changes in energy and carbon metabolisms significantly affected the relative abundance of rings in the core lipids of DS80. These observations highlight the need to better constrain metabolic parameters, in addition to environmental factors, which may influence changes in membrane physiology in Archaea. Such consideration would be particularly important for studying archaeal lipids from habitats that experience frequent environmental fluctuations and/or where metabolically diverse archaea thrive.
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Affiliation(s)
- Jeemin H. Rhim
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, California, USA
| | - Alice Zhou
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Maximiliano J. Amenabar
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Grayson M. Boyer
- School of Earth and Space Exploration, Arizona State University, Tempe, Arizona, USA
| | - Felix J. Elling
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
- Leibniz-Laboratory for Radiometric Dating and Isotope Research, Christian-Albrecht University of Kiel, Kiel, Germany
| | - Yuki Weber
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Ann Pearson
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - William D. Leavitt
- Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire, USA
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire, USA
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3
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Cryo-electron structures of the extreme thermostable enzymes Sulfur Oxygenase Reductase and Lumazine Synthase. PLoS One 2022; 17:e0275487. [PMID: 36191023 PMCID: PMC9529111 DOI: 10.1371/journal.pone.0275487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/18/2022] [Indexed: 11/05/2022] Open
Abstract
Thermostable enzymes have the potential for use in a wide variety of biotechnological applications. Cryo-electron microscopy (cryo-EM) enables the imaging of biomolecules in their native aqueous environment. Here, we present high resolution cryo-EM structures of two thermostable enzymes that exhibit multimeric cage-like structures arranged into two different point-group symmetries. First, we determined the structure of the Sulfur Oxygenase Reductase (SOR) enzyme that catalyzes both the oxygenation and disproportionation of elemental sulfur in Archea and is composed of 24 homomeric units each of MW ≃ 35 kDa arranged in octahedral symmetry. The structure of SOR from Acidianus ambivalens (7X9W) was determined at 2.78 Å resolution. The active site of each subunit inside the central nanocompartment is composed of Fe3+ coordinated to two water molecules and the three amino acids (H86, H90 and E114). Second, we determined the structure of Lumazine Synthase (LS) from Aquifex aeolicus (7X7M) at 2.33 Å resolution. LS forms a cage-like structure consisting of 60 identical subunits each of MW ≃ 15 kDa arranged in a strict icosahedral symmetry. The LS subunits are interconnected by ion-pair network. Due to their thermostability and relatively easy purification scheme, both SOR and LS can serve as a model for the catalytic and structural characterization of biocatalysts as well as a benchmark for cryo-EM sample preparation, optimization of the acquisition parameters and 3D reconstruction.
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Pal N, Sinha S, Shivani, Chakraborty M. A review on bacterial and archaeal thermostable sulfur oxidoreductases (SORS)-an insight into the biochemical, molecular and in-silico structural comparative analysis of a neglected thermostable enzyme of industrial significance. Arch Microbiol 2022; 204:655. [PMID: 36175582 DOI: 10.1007/s00203-022-03256-3] [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: 03/08/2022] [Revised: 09/08/2022] [Accepted: 09/12/2022] [Indexed: 11/02/2022]
Abstract
Diverse thermophilic microorganisms with the potential to withstand extreme physiological conditions have long been investigated and explored for human commercial benefit. Thermozymes with distinct functional and structural properties isolated from these thermophiles are known to have high thermostability without significant loss of specific enzyme activity. Thermophiles isolated and characterised from the thermophilic ecological niche of India are well documented. There is a plethora of work in the literature emphasising its industrial significance. However, in-depth knowledge of the thermophilic oxidoreductase group of enzymes (Oxizymes) is restricted. Sulfur Oxygenase Reductases or Sulfur Oxygen-Reductases (SORs) are a group of thermophilic oxizymes reported predominantly from thermophilic and mesophilic archaea and bacteria, which catalyse oxygen-dependent disproportionation reactions of elemental sulfur, producing sulfite, thiosulfate, and sulphide. There have been few reports on isolated and characterised SORs from the Indian geothermal niche. The review article will highlight the SORs reported till date with a concise overview of different archaeal and bacterial species producing the enzymes. Based on the literature available till date, characteristics including physico-chemical properties, amino acid sequence homology, conserved motifs and their 3D structure comparison have been discussed. In-silico sequence and structure level preliminary comparative analysis of various SORs has also been discussed. However, a few SORs whose structural information is not reported in the protein data bank have been modelled to enrich our analysis.
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Affiliation(s)
- Nirmalya Pal
- University Institute of Biotechnology, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India
| | - Sanjana Sinha
- NMR Micro-Imaging and Spectroscopy Laboratory, Centre for Cellular and Molecular Biology, Uppal Rd, IICT Colony, Habsiguda, Hyderabad, 500007, Telangana, India
| | - Shivani
- University Institute of Biotechnology, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India
| | - Mitun Chakraborty
- Department of Biotechnology Engineering and Food Technology, University Institute of Engineering, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India.
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5
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Ferreira P, Fernandes P, Ramos M. The archaeal non-heme iron-containing Sulfur Oxygenase Reductase. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2021.214358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liu LJ, Jiang Z, Wang P, Qin YL, Xu W, Wang Y, Liu SJ, Jiang CY. Physiology, Taxonomy, and Sulfur Metabolism of the Sulfolobales, an Order of Thermoacidophilic Archaea. Front Microbiol 2021; 12:768283. [PMID: 34721370 PMCID: PMC8551704 DOI: 10.3389/fmicb.2021.768283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022] Open
Abstract
The order Sulfolobales (phylum Crenarchaeota) is a group of thermoacidophilic archaea. The first member of the Sulfolobales was discovered in 1972, and current 23 species are validly named under the International Code of Nomenclature of Prokaryotes. The majority of members of the Sulfolobales is obligately or facultatively chemolithoautotrophic. When they grow autotrophically, elemental sulfur or reduced inorganic sulfur compounds are their energy sources. Therefore, sulfur metabolism is the most important physiological characteristic of the Sulfolobales. The functions of some enzymes and proteins involved in sulfur reduction, sulfur oxidation, sulfide oxidation, thiosulfate oxidation, sulfite oxidation, tetrathionate hydrolysis, and sulfur trafficking have been determined. In this review, we describe current knowledge about the physiology, taxonomy, and sulfur metabolism of the Sulfolobales, and note future challenges in this field.
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Affiliation(s)
- Li-Jun Liu
- School of Basic Medical Science, the Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Xi'an Medical University, Xi'an, China.,Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Zhen Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Pei Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Ya-Ling Qin
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wen Xu
- School of Basic Medical Science, the Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Xi'an Medical University, Xi'an, China.,Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Yang Wang
- School of Basic Medical Science, the Xi'an Key Laboratory of Pathogenic Microorganism and Tumor Immunity, Xi'an Medical University, Xi'an, China.,Key Laboratory of Resources Biology and Biotechnology in Western China, Ministry of Education, College of Life Sciences, Northwest University, Xi'an, China
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cheng-Ying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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7
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Counts JA, Willard DJ, Kelly RM. Life in hot acid: a genome-based reassessment of the archaeal order Sulfolobales. Environ Microbiol 2021; 23:3568-3584. [PMID: 32776389 PMCID: PMC10560490 DOI: 10.1111/1462-2920.15189] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 01/07/2023]
Abstract
The order Sulfolobales was one of the first named Archaeal lineages, with globally distributed members from terrestrial thermal acid springs (pH < 4; T > 65°C). The Sulfolobales represent broad metabolic capabilities, ranging from lithotrophy, based on inorganic iron and sulfur biotransformations, to autotrophy, to chemoheterotrophy in less acidophilic species. Components of the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation cycle, as well as sulfur oxidation, are nearly universally conserved, although dissimilatory sulfur reduction and disproportionation (Acidianus, Stygiolobus and Sulfurisphaera) and iron oxidation (Acidianus, Metallosphaera, Sulfurisphaera, Sulfuracidifex and Sulfodiicoccus) are limited to fewer lineages. Lithotrophic marker genes appear more often in highly acidophilic lineages. Despite the presence of facultative anaerobes and one confirmed obligate anaerobe, oxidase complexes (fox, sox, dox and a new putative cytochrome bd) are prevalent in many species (even facultative/obligate anaerobes), suggesting a key role for oxygen among the Sulfolobales. The presence of fox genes tracks with a putative antioxidant OsmC family peroxiredoxin, an indicator of oxidative stress derived from mixing reactive metals and oxygen. Extreme acidophily appears to track inversely with heterotrophy but directly with lithotrophy. Recent phylogenetic re-organization efforts are supported by the comparative genomics here, although several changes are proposed, including the expansion of the genus Saccharolobus.
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Affiliation(s)
- James A. Counts
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Daniel J. Willard
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
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Parveen S, Akhtar N, Akram J. Genomic analysis provides insights into the Gordonia sp. W3S5 taxonomy and sulfur metabolism-related genes. 3 Biotech 2021; 11:300. [PMID: 34194893 DOI: 10.1007/s13205-021-02850-4] [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: 10/13/2020] [Accepted: 05/17/2021] [Indexed: 10/21/2022] Open
Abstract
The Gordonia sp. W3S5, isolated from oil-polluted soil samples can remove sulfur from a variety of symmetric and asymmetric thiophenic compounds and diesel oil. Its draft genome sequence was comprised of 49 contigs, total genome size 4.86 Mb, and a G + C content of 67.50%. According to the current bacterial taxonomy procedures (16S rRNA gene sequence and overall genome-related index), the W3S5 was affiliated to Gordonia rubripertincta. Rapid Annotation using Subsystem Technology (ClassicRAST) server revealed that the W3S5 contains 4435 coding sequences, 404 subsystems and 60 sulfur metabolism genes. The RAST comparative genomic analysis showed that the genes connected with organic sulfur metabolism are majorly related to ssu and dszABC operons. Moreover, the comparison of orthologous gene clusters using OrthoVenn2 web server revealed a total of 4869 clusters, 2685 core orthologs, 632 shared orthologs and 112 unique ortholog clusters among the W3S5 and other type strains of Gordonia. This is the first report describing genome-based characterization of a Gordonia rubripertincta strain desulfurizing thiophenic compounds and diesel oil. The desulfurization potential of Gordonia rubripertincta W3S5 and genomic analyses revealed it as a valuable biocatalyst for process development to desulfurize a broad range of thiophenic sulfur-containing compounds, which are a major component of organic sulfur in petroleum oil. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02850-4.
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9
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Sato Y, Yabuki T, Adachi N, Moriya T, Arakawa T, Kawasaki M, Yamada C, Senda T, Fushinobu S, Wakagi T. Crystallographic and cryogenic electron microscopic structures and enzymatic characterization of sulfur oxygenase reductase from Sulfurisphaera tokodaii. JOURNAL OF STRUCTURAL BIOLOGY-X 2020; 4:100030. [PMID: 32775998 PMCID: PMC7398979 DOI: 10.1016/j.yjsbx.2020.100030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/20/2020] [Accepted: 06/30/2020] [Indexed: 02/07/2023]
Abstract
Sulfur oxygenase reductase (SOR) was biochemically and structurally characterized. High resolution structures of SOR were determined by crystallography and cryo-EM. Twenty-four identical subunits of SOR form a hollow sphere. Catalytic components exhibited different features in the crystal and cryo-EM structures.
Sulfur oxygenase reductases (SORs) are present in thermophilic and mesophilic archaea and bacteria, and catalyze oxygen-dependent oxygenation and disproportionation of elemental sulfur. SOR has a hollow, spherical homo-24-mer structure and reactions take place at active sites inside the chamber. The crystal structures of SORs from Acidianus species have been reported. However, the states of the active site components (mononuclear iron and cysteines) and the entry and exit paths of the substrate and products are still in dispute. Here, we report the biochemical and structural characterizations of SORs from the thermoacidophilic archaeon Sulfurisphaera tokodaii (StSOR) and present high-resolution structures determined by X-ray crystallography and cryogenic electron microscopy (cryo-EM). The crystal structure of StSOR was determined at 1.73 Å resolution. At the catalytic center, iron is ligated to His86, His90, Glu114, and two water molecules. Three conserved cysteines in the cavity are located 9.5–13 Å from the iron and were observed as free thiol forms. A mutational analysis indicated that the iron and one of the cysteines (Cys31) were essential for both activities. The cryo-EM structure was determined at 2.24 Å resolution using an instrument operating at 200 kV. The two structures determined by different methodologies showed similar main chain traces, but the maps exhibited different features at catalytically important components. A possible role of StSOR in the sulfur metabolism of S. tokodaii (an obligate aerobe) is discussed based on this study. Given the high resolution achieved in this study, StSOR was shown to be a good benchmark sample for cryo-EM.
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Key Words
- AaSOR, Acidianus ambivalens SOR
- AqSOR, Aquifex aeolicus SOR
- Archaea
- AtSOR, Acidianus tengchongensis SOR
- CTF, contrast transfer function
- Cryogenic electron microscopy
- DTNB, 5,5′-dithiobis(2-nitrobenzoic acid)
- FSC, Fourier shell correlation
- HnSOR, Halothiobacillus neapolitanus SOR
- Nonheme mononuclear iron center
- PAGE, polyacrylamide gel electrophoresis
- RMSD, root mean square deviation
- SD, standard deviation
- SDS, sodium dodecyl sulfate
- SOR, sulfur oxygenase reductase
- SbSOR, Sulfobacillus thermosulfidooxidans SOR
- StSOR, Sulfurisphaera tokodaii SOR
- Sulfur metabolism
- TpSOR, Thioalkalivibrio paradoxus SOR
- X-ray crystallography
- cryo-EM, cryogenic electron microscopy
- pCMB, p-chloromercuribenzoate
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Affiliation(s)
- Yuta Sato
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takashi Yabuki
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Naruhiko Adachi
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Toshio Moriya
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Takatoshi Arakawa
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masato Kawasaki
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Chihaya Yamada
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toshiya Senda
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takayoshi Wakagi
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Wang P, Li LZ, Qin YL, Liang ZL, Li XT, Yin HQ, Liu LJ, Liu SJ, Jiang CY. Comparative Genomic Analysis Reveals the Metabolism and Evolution of the Thermophilic Archaeal Genus Metallosphaera. Front Microbiol 2020; 11:1192. [PMID: 32655516 PMCID: PMC7325606 DOI: 10.3389/fmicb.2020.01192] [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: 01/16/2020] [Accepted: 05/11/2020] [Indexed: 01/15/2023] Open
Abstract
Members of the genus Metallosphaera are widely found in sulfur-rich and metal-laden environments, but their physiological and ecological roles remain poorly understood. Here, we sequenced Metallosphaera tengchongensis Ric-A, a strain isolated from the Tengchong hot spring in Yunnan Province, China, and performed a comparative genome analysis with other Metallosphaera genomes. The genome of M. tengchongensis had an average nucleotide identity (ANI) of approximately 70% to that of Metallosphaera cuprina. Genes sqr, tth, sir, tqo, hdr, tst, soe, and sdo associated with sulfur oxidation, and gene clusters fox and cbs involved in iron oxidation existed in all Metallosphaera genomes. However, the adenosine-5'-phosphosulfate (APS) pathway was only detected in Metallosphaera sedula and Metallosphaera yellowstonensis, and several subunits of fox cluster were lost in M. cuprina. The complete 3-hydroxypropionate/4-hydroxybutyrate cycle and dicarboxylate/4-hydroxybutyrate cycle involved in carbon fixation were found in all Metallosphaera genomes. A large number of gene family gain events occurred in M. yellowstonensis and M. sedula, whereas gene family loss events occurred frequently in M. cuprina. Pervasive strong purifying selection was found acting on the gene families of Metallosphaera, of which transcription-related genes underwent the strongest purifying selection. In contrast, genes related to prophages, transposons, and defense mechanisms were under weaker purifying pressure. Taken together, this study expands knowledge of the genomic traits of Metallosphaera species and sheds light on their evolution.
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Affiliation(s)
- Pei Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Liang Zhi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Ya Ling Qin
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zong Lin Liang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiu Tong Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Hua Qun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Li Jun Liu
- Department of Pathogen Biology, School of Basic Medical Science, Xi’an Medical University, Xi’an, China
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Cheng-Ying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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11
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Akhtar N, Ghauri MA, Akhtar K, Parveen S, Farooq M, Ali A, Schierack P. Comparative Analysis of Draft Genome Sequence of Rhodococcus sp. Eu-32 with Other Rhodococcus Species for Its Taxonomic Status and Sulfur Metabolism Potential. Curr Microbiol 2019; 76:1207-1214. [PMID: 31300840 DOI: 10.1007/s00284-019-01737-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/03/2019] [Indexed: 10/26/2022]
Abstract
Rhodococcus sp. Eu-32 has shown an extended novel dibenzothiophene desulfurization sulfur-specific 4S pathway and could remove significant amounts of organic sulfur from coal. Here, we present the draft genome sequence of Eu-32 with a genome size of approximately 5.61 Mb, containing 5065 protein coding sequences with a G+C content of 65.1%. The Rhodococcus sp. Eu-32 showed ~ 99% identity at the 16S rRNA gene sequence level while < 34% digital DNA-DNA hybridization and < 81% average nucleotide identity values with the genome sequence of most closely related known Rhodococcus species, suggesting that it is taxonomically different from the already reported Rhodococcus species. Among the annotated genes, 90 are involved in the metabolism of sulfur. Comparative genome analysis suggests many commonalities in sulfur metabolism gene sets that may have evolved due to many factors including ecological pressures. Our study and the genome sequence data will be available for further research and will provide insights into potential biotechnological and industrial applications of this bacterium.
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Affiliation(s)
- Nasrin Akhtar
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Muhammad A Ghauri
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Kalsoom Akhtar
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan
| | - Sana Parveen
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan
| | - Muhammad Farooq
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan
| | - Aamir Ali
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P. O. Box 577, Jhang Road, Faisalabad, Pakistan
| | - Peter Schierack
- Institute for Biotechnology, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
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12
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Chen JH, Yu LJ, Boussac A, Wang-Otomo ZY, Kuang T, Shen JR. Properties and structure of a low-potential, penta-heme cytochrome c 552 from a thermophilic purple sulfur photosynthetic bacterium Thermochromatium tepidum. PHOTOSYNTHESIS RESEARCH 2019; 139:281-293. [PMID: 29691716 DOI: 10.1007/s11120-018-0507-y] [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: 02/28/2018] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
The thermophilic purple sulfur bacterium Thermochromatium tepidum possesses four main water-soluble redox proteins involved in the electron transfer behavior. Crystal structures have been reported for three of them: a high potential iron-sulfur protein, cytochrome c', and one of two low-potential cytochrome c552 (which is a flavocytochrome c) have been determined. In this study, we purified another low-potential cytochrome c552 (LPC), determined its N-terminal amino acid sequence and the whole gene sequence, characterized it with absorption and electron paramagnetic spectroscopy, and solved its high-resolution crystal structure. This novel cytochrome was found to contain five c-type hemes. The overall fold of LPC consists of two distinct domains, one is the five heme-containing domain and the other one is an Ig-like domain. This provides a representative example for the structures of multiheme cytochromes containing an odd number of hemes, although the structures of multiheme cytochromes with an even number of hemes are frequently seen in the PDB database. Comparison of the sequence and structure of LPC with other proteins in the databases revealed several characteristic features which may be important for its functioning. Based on the results obtained, we discuss the possible intracellular function of this LPC in Tch. tepidum.
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Affiliation(s)
- Jing-Hua Chen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
- University of Chinese Academy of Sciences, Yuquan Rd, Shijingshan District, Beijing, 100049, China
| | - Long-Jiang Yu
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan
| | - Alain Boussac
- I2BC, SB2SM, CNRS UMR 9198, CEA Saclay, 91191, Gif-sur-Yvette, France
| | | | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, No. 20, Nanxincun, Xiangshan, Beijing, 100093, China.
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
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Wang R, Lin JQ, Liu XM, Pang X, Zhang CJ, Yang CL, Gao XY, Lin CM, Li YQ, Li Y, Lin JQ, Chen LX. Sulfur Oxidation in the Acidophilic Autotrophic Acidithiobacillus spp. Front Microbiol 2019; 9:3290. [PMID: 30687275 PMCID: PMC6335251 DOI: 10.3389/fmicb.2018.03290] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/18/2018] [Indexed: 12/12/2022] Open
Abstract
Sulfur oxidation is an essential component of the earth's sulfur cycle. Acidithiobacillus spp. can oxidize various reduced inorganic sulfur compounds (RISCs) with high efficiency to obtain electrons for their autotrophic growth. Strains in this genus have been widely applied in bioleaching and biological desulfurization. Diverse sulfur-metabolic pathways and corresponding regulatory systems have been discovered in these acidophilic sulfur-oxidizing bacteria. The sulfur-metabolic enzymes in Acidithiobacillus spp. can be categorized as elemental sulfur oxidation enzymes (sulfur dioxygenase, sulfur oxygenase reductase, and Hdr-like complex), enzymes in thiosulfate oxidation pathways (tetrathionate intermediate thiosulfate oxidation (S4I) pathway, the sulfur oxidizing enzyme (Sox) system and thiosulfate dehydrogenase), sulfide oxidation enzymes (sulfide:quinone oxidoreductase) and sulfite oxidation pathways/enzymes. The two-component systems (TCSs) are the typical regulation elements for periplasmic thiosulfate metabolism in these autotrophic sulfur-oxidizing bacteria. Examples are RsrS/RsrR responsible for S4I pathway regulation and TspS/TspR for Sox system regulation. The proposal of sulfur metabolic and regulatory models provide new insights and overall understanding of the sulfur-metabolic processes in Acidithiobacillus spp. The future research directions and existing barriers in the bacterial sulfur metabolism are also emphasized here and the breakthroughs in these areas will accelerate the research on the sulfur oxidation in Acidithiobacillus spp. and other sulfur oxidizers.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Jian-Qun Lin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Lin-Xu Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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Rühl P, Haas P, Seipel D, Becker J, Kletzin A. Persulfide Dioxygenase From Acidithiobacillus caldus: Variable Roles of Cysteine Residues and Hydrogen Bond Networks of the Active Site. Front Microbiol 2018; 9:1610. [PMID: 30072973 PMCID: PMC6060420 DOI: 10.3389/fmicb.2018.01610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 06/27/2018] [Indexed: 12/16/2022] Open
Abstract
Persulfide dioxygenases (PDOs) are abundant in Bacteria and also crucial for H2S detoxification in mitochondria. One of the two pdo-genes of the acidophilic bacterium Acidithiobacillus caldus was expressed in Escherichia coli. The protein (AcPDO) had 0.77 ± 0.1 Fe/subunit and an average specific sulfite formation activity of 111.5 U/mg protein (Vmax) at 40°C and pH 7.5 with sulfur and GSH following Michaelis-Menten kinetics. KM for GSH and Kcat were 0.5 mM and 181 s-1, respectively. Glutathione persulfide (GSSH) as substrate gave a sigmoidal curve with a Vmax of 122.3 U/mg protein, a Kcat of 198 s-1 and a Hill coefficient of 2.3 ± 0.22 suggesting positive cooperativity. Gel permeation chromatography and non-denaturing gels showed mostly tetramers. The temperature optimum was 40-45°C, the melting point 63 ± 1.3°C in thermal unfolding experiments, whereas low activity was measurable up to 95°C. Site-directed mutagenesis showed that residues located in the predicted GSH/GSSH binding site and in the central hydrogen bond networks including the iron ligands are essential for activity. Among these, the R139A, D141A, and H171A variants were inactive concomitant to a decrease of their melting points by 3-8 K. Other variants were inactivated without significant melting point change. Two out of five cysteines are likewise essential, both of which lie presumably in close proximity at the surface of the protein (C87 and C224). MalPEG labeling experiments suggests that they form a disulfide bridge. The reducing agent Tris(2-carboxyethyl)phosphine was inhibitory besides N-ethylmaleimide and iodoacetamide suggesting an involvement of cysteines and the disulfide in catalysis and/or protein stabilization. Mass spectrometry revealed modification of C87, C137, and C224 by 305 mass units equivalent to GSH after incubation with GSSH and with GSH in case of the C87A and C224A variants. The results of this study suggest that disulfide formation between the two essential surface-exposed cysteines and Cys-S-glutathionylation serve as a protective mechanism against uncontrolled thiol oxidation and the associated loss of enzyme activity.
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Affiliation(s)
| | | | | | | | - Arnulf Kletzin
- Department of Biology, Sulfur Biochemistry and Microbial Bioenergetics, Technische Universität Darmstadt, Darmstadt, Germany
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Bioelectrochemical Changes during the Early Stages of Chalcopyrite Interaction with Acidithiobacillus Thiooxidans and Leptospirillum sp. MINERALS 2017. [DOI: 10.3390/min7090156] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Straub CT, Zeldes BM, Schut GJ, Adams MWW, Kelly RM. Extremely thermophilic energy metabolisms: biotechnological prospects. Curr Opin Biotechnol 2017; 45:104-112. [DOI: 10.1016/j.copbio.2017.02.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/14/2017] [Accepted: 02/24/2017] [Indexed: 12/16/2022]
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A Sulfur Oxygenase from the Haloalkaliphilic Bacterium Thioalkalivibrio paradoxus with Atypically Low Reductase Activity. J Bacteriol 2017; 199:JB.00675-16. [PMID: 27920296 DOI: 10.1128/jb.00675-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 11/28/2016] [Indexed: 01/26/2023] Open
Abstract
Sequence comparisons showed that the sulfur oxygenase reductase (SOR) of the haloalkaliphilic bacterium Thioalkalivibrio paradoxus Arh 1 (TpSOR) is branching deeply within dendrograms of these proteins (29 to 34% identity). A synthetic gene encoding TpSOR expressed in Escherichia coli resulted in a protein 14.7 ± 0.9 nm in diameter and an apparent molecular mass of 556 kDa. Sulfite and thiosulfate were formed from elemental sulfur in a temperature range of 10 to 98°C (optimum temperature ≈ 80°C) and a pH range of 6 to 11.5 (optimum pH ≈ 9; 308 ± 78 U/mg of protein). Sulfide formation had a maximum specific activity of 0.03 U/mg, or <1% of the corresponding activity of other SORs. Hence, reductase activity seems not to be an integral part of the reaction mechanism. TpSOR was most active at NaCl or glycine betaine concentrations of 0 to 1 M, although 0.2% of the maximal activity was detected even at 5 M NaCl and 4 M betaine. The melting point of TpSOR was close to 80°C, when monitored by circular dichroism spectroscopy or differential scanning fluorimetry; however, the denaturation kinetics were slow: 55% of the residual activity remained after 25 min of incubation at 80°C. Site-directed mutagenesis showed that the active-site residue Cys44 is essential for activity, whereas alanine mutants of the two other conserved cysteines retained about 0.5% residual activity. A model of the sulfur metabolism in T. paradoxus is discussed. IMPORTANCE Sulfur oxygenase reductases (SORs) are the only enzymes catalyzing an oxygen-dependent disproportionation of elemental sulfur and/or polysulfides to sulfite, thiosulfate, and hydrogen sulfide. SORs are known from mesophilic and extremophilic archaea and bacteria. All SORs seem to form highly thermostable 24-subunit hollow spheres. They carry a low-potential mononuclear nonheme iron in the active site and an indispensable cysteine; however, their exact reaction mechanisms are unknown. Typically, the reductase activity of SORs is in the range of 5 to 50% of the oxygenase activity, but mutagenesis studies had so far failed to identify residues crucial for the reductase reaction. We describe here the first SOR, which is almost devoid of the reductase reaction and which comes from a haloalkaliphilic bacterium.
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Dai X, Wang H, Zhang Z, Li K, Zhang X, Mora-López M, Jiang C, Liu C, Wang L, Zhu Y, Hernández-Ascencio W, Dong Z, Huang L. Genome Sequencing of Sulfolobus sp. A20 from Costa Rica and Comparative Analyses of the Putative Pathways of Carbon, Nitrogen, and Sulfur Metabolism in Various Sulfolobus Strains. Front Microbiol 2016; 7:1902. [PMID: 27965637 PMCID: PMC5127849 DOI: 10.3389/fmicb.2016.01902] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 11/14/2016] [Indexed: 11/13/2022] Open
Abstract
The genome of Sulfolobus sp. A20 isolated from a hot spring in Costa Rica was sequenced. This circular genome of the strain is 2,688,317 bp in size and 34.8% in G+C content, and contains 2591 open reading frames (ORFs). Strain A20 shares ~95.6% identity at the 16S rRNA gene sequence level and <30% DNA-DNA hybridization (DDH) values with the most closely related known Sulfolobus species (i.e., Sulfolobus islandicus and Sulfolobus solfataricus), suggesting that it represents a novel Sulfolobus species. Comparison of the genome of strain A20 with those of the type strains of S. solfataricus, Sulfolobus acidocaldarius, S. islandicus, and Sulfolobus tokodaii, which were isolated from geographically separated areas, identified 1801 genes conserved among all Sulfolobus species analyzed (core genes). Comparative genome analyses show that central carbon metabolism in Sulfolobus is highly conserved, and enzymes involved in the Entner-Doudoroff pathway, the tricarboxylic acid cycle and the CO2 fixation pathways are predominantly encoded by the core genes. All Sulfolobus species encode genes required for the conversion of ammonium into glutamate/glutamine. Some Sulfolobus strains have gained the ability to utilize additional nitrogen source such as nitrate (i.e., S. islandicus strain REY15A, LAL14/1, M14.25, and M16.27) or urea (i.e., S. islandicus HEV10/4, S. tokodaii strain7, and S. metallicus DSM 6482). The strategies for sulfur metabolism are most diverse and least understood. S. tokodaii encodes sulfur oxygenase/reductase (SOR), whereas both S. islandicus and S. solfataricus contain genes for sulfur reductase (SRE). However, neither SOR nor SRE genes exist in the genome of strain A20, raising the possibility that an unknown pathway for the utilization of elemental sulfur may be present in the strain. The ability of Sulfolobus to utilize nitrate or sulfur is encoded by a gene cluster flanked by IS elements or their remnants. These clusters appear to have become fixed at a specific genomic site in some strains and lost in other strains during the course of evolution. The versatility in nitrogen and sulfur metabolism may represent adaptation of Sulfolobus to thriving in different habitats.
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Affiliation(s)
- Xin Dai
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
| | - Haina Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
| | - Zhenfeng Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Kuan Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Xiaoling Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Marielos Mora-López
- Center for Research in Cell and Molecular Biology, Universidad de Costa Rica San José, Costa Rica
| | - Chengying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Chang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
| | - Li Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Yaxin Zhu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | | | - Zhiyang Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China
| | - Li Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of SciencesBeijing, China; College of Life Sciences, University of Chinese Academy of SciencesBeijing, China
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19
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Findlay AJ. Microbial impact on polysulfide dynamics in the environment. FEMS Microbiol Lett 2016; 363:fnw103. [DOI: 10.1093/femsle/fnw103] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 11/12/2022] Open
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20
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Sulfur Oxygenase Reductase (Sor) in the Moderately Thermoacidophilic Leaching Bacteria: Studies in Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus. Microorganisms 2015; 3:707-24. [PMID: 27682113 PMCID: PMC5023260 DOI: 10.3390/microorganisms3040707] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 10/01/2015] [Accepted: 10/10/2015] [Indexed: 12/15/2022] Open
Abstract
The sulfur oxygenase reductase (Sor) catalyzes the oxygen dependent disproportionation of elemental sulfur, producing sulfite, thiosulfate and sulfide. Being considered an “archaeal like” enzyme, it is also encoded in the genomes of some acidophilic leaching bacteria such as Acidithiobacillus caldus, Acidithiobacillus thiooxidans, Acidithiobacillus ferrivorans and Sulfobacillus thermosulfidooxidans, among others. We measured Sor activity in crude extracts from Sb. thermosulfidooxidans DSM 9293T. The optimum temperature for its oxygenase activity was achieved at 75 °C, confirming the “thermophilic” nature of this enzyme. Additionally, a search for genes probably involved in sulfur metabolism in the genome sequence of Sb. thermosulfidooxidans DSM 9293T was done. Interestingly, no sox genes were found. Two sor genes, a complete heterodisulfidereductase (hdr) gene cluster, three tetrathionate hydrolase (tth) genes, three sulfide quinonereductase (sqr), as well as the doxD component of a thiosulfate quinonereductase (tqo) were found. Seven At. caldus strains were tested for Sor activity, which was not detected in any of them. We provide evidence that an earlier reported Sor activity from At. caldus S1 and S2 strains most likely was due to the presence of a Sulfobacillus contaminant.
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Justice NB, Norman A, Brown CT, Singh A, Thomas BC, Banfield JF. Comparison of environmental and isolate Sulfobacillus genomes reveals diverse carbon, sulfur, nitrogen, and hydrogen metabolisms. BMC Genomics 2014; 15:1107. [PMID: 25511286 PMCID: PMC4378227 DOI: 10.1186/1471-2164-15-1107] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/27/2014] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Bacteria of the genus Sulfobacillus are found worldwide as members of microbial communities that accelerate sulfide mineral dissolution in acid mine drainage environments (AMD), acid-rock drainage environments (ARD), as well as in industrial bioleaching operations. Despite their frequent identification in these environments, their role in biogeochemical cycling is poorly understood. RESULTS Here we report draft genomes of five species of the Sulfobacillus genus (AMDSBA1-5) reconstructed by cultivation-independent sequencing of biofilms sampled from the Richmond Mine (Iron Mountain, CA). Three of these species (AMDSBA2, AMDSBA3, and AMDSBA4) have no cultured representatives while AMDSBA1 is a strain of S. benefaciens, and AMDSBA5 a strain of S. thermosulfidooxidans. We analyzed the diversity of energy conservation and central carbon metabolisms for these genomes and previously published Sulfobacillus genomes. Pathways of sulfur oxidation vary considerably across the genus, including the number and type of subunits of putative heterodisulfide reductase complexes likely involved in sulfur oxidation. The number and type of nickel-iron hydrogenase proteins varied across the genus, as does the presence of different central carbon pathways. Only the AMDSBA3 genome encodes a dissimilatory nitrate reducatase and only the AMDSBA5 and S. thermosulfidooxidans genomes encode assimilatory nitrate reductases. Within the genus, AMDSBA4 is unusual in that its electron transport chain includes a cytochrome bc type complex, a unique cytochrome c oxidase, and two distinct succinate dehydrogenase complexes. CONCLUSIONS Overall, the results significantly expand our understanding of carbon, sulfur, nitrogen, and hydrogen metabolism within the Sulfobacillus genus.
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Affiliation(s)
- Nicholas B Justice
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
- />Physical Biosciences Division, Lawrence Berkeley National Lab, Berkeley, CA USA
| | - Anders Norman
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
- />Section for Infection Microbiology, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Christopher T Brown
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
| | - Andrea Singh
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
| | - Brian C Thomas
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
| | - Jillian F Banfield
- />Department of Earth and Planetary Science, University of California, Berkeley, CA 94720 USA
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Kanao T, Nakayama H, Kato M, Kamimura K. The sole cysteine residue (Cys301) of tetrathionate hydrolase from Acidithiobacillus ferrooxidans does not play a role in enzyme activity. Biosci Biotechnol Biochem 2014; 78:2030-5. [PMID: 25144400 DOI: 10.1080/09168451.2014.948374] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Cysteine residues are absolutely indispensable for the reactions of almost all enzymes involved in the dissimilatory oxidation pathways of reduced inorganic sulfur compounds. Tetrathionate hydrolase from the acidophilic iron- and sulfur-oxidizing bacterium Acidithiobacillus ferrooxidans (Af-Tth) catalyzes tetrathionate hydrolysis to generate elemental sulfur, thiosulfate, and sulfate. Af-Tth is a key enzyme in the dissimilatory sulfur oxidation pathway in this bacterium. Only one cysteine residue (Cys301) has been identified in the deduced amino acid sequence of the Af-Tth gene. In order to clarify the role of the sole cysteine residue, a site-specific mutant enzyme (C301A) was generated. No difference was observed in the retention volumes of the wild-type and mutant Af-Tth enzymes by gel-filtration column chromatography, and surprisingly the enzyme activities measured in the cysteine-deficient and wild-type enzymes were the same. These results suggest that the sole cysteine residue (Cys301) in Af-Tth is involved in neither the tetrathionate hydrolysis reaction nor the subunit assembly. Af-Tth may thus have a novel cysteine-independent reaction mechanism.
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Affiliation(s)
- Tadayoshi Kanao
- a Department of Biofunctional Chemistry, Division of Agricultural and Life Science, Graduate School of Environmental and Life Science , Okayama University , Okayama , Japan
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Yin H, Zhang X, Li X, He Z, Liang Y, Guo X, Hu Q, Xiao Y, Cong J, Ma L, Niu J, Liu X. Whole-genome sequencing reveals novel insights into sulfur oxidation in the extremophile Acidithiobacillus thiooxidans. BMC Microbiol 2014; 14:179. [PMID: 24993543 PMCID: PMC4109375 DOI: 10.1186/1471-2180-14-179] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 06/19/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Acidithiobacillus thiooxidans (A. thiooxidans), a chemolithoautotrophic extremophile, is widely used in the industrial recovery of copper (bioleaching or biomining). The organism grows and survives by autotrophically utilizing energy derived from the oxidation of elemental sulfur and reduced inorganic sulfur compounds (RISCs). However, the lack of genetic manipulation systems has restricted our exploration of its physiology. With the development of high-throughput sequencing technology, the whole genome sequence analysis of A. thiooxidans has allowed preliminary models to be built for genes/enzymes involved in key energy pathways like sulfur oxidation. RESULTS The genome of A. thiooxidans A01 was sequenced and annotated. It contains key sulfur oxidation enzymes involved in the oxidation of elemental sulfur and RISCs, such as sulfur dioxygenase (SDO), sulfide quinone reductase (SQR), thiosulfate:quinone oxidoreductase (TQO), tetrathionate hydrolase (TetH), sulfur oxidizing protein (Sox) system and their associated electron transport components. Also, the sulfur oxygenase reductase (SOR) gene was detected in the draft genome sequence of A. thiooxidans A01, and multiple sequence alignment was performed to explore the function of groups of related protein sequences. In addition, another putative pathway was found in the cytoplasm of A. thiooxidans, which catalyzes sulfite to sulfate as the final product by phosphoadenosine phosphosulfate (PAPS) reductase and adenylylsulfate (APS) kinase. This differs from its closest relative Acidithiobacillus caldus, which is performed by sulfate adenylyltransferase (SAT). Furthermore, real-time quantitative PCR analysis showed that most of sulfur oxidation genes were more strongly expressed in the S0 medium than that in the Na2S2O3 medium at the mid-log phase. CONCLUSION Sulfur oxidation model of A. thiooxidans A01 has been constructed based on previous studies from other sulfur oxidizing strains and its genome sequence analyses, providing insights into our understanding of its physiology and further analysis of potential functions of key sulfur oxidation genes.
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Affiliation(s)
- Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xian Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xiaoqi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Zhili He
- Institute for Environmental Genomics, University of Oklahoma, Norman, OK, USA
| | - Yili Liang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xue Guo
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Qi Hu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Yunhua Xiao
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jing Cong
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Liyuan Ma
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jiaojiao Niu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
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The F420-Reducing [NiFe]-Hydrogenase Complex from Methanothermobacter marburgensis, the First X-ray Structure of a Group 3 Family Member. J Mol Biol 2014; 426:2813-26. [DOI: 10.1016/j.jmb.2014.05.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/02/2014] [Accepted: 05/23/2014] [Indexed: 11/21/2022]
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Guo X, Yin H, Liang Y, Hu Q, Zhou X, Xiao Y, Ma L, Zhang X, Qiu G, Liu X. Comparative genome analysis reveals metabolic versatility and environmental adaptations of Sulfobacillus thermosulfidooxidans strain ST. PLoS One 2014; 9:e99417. [PMID: 24940621 PMCID: PMC4062416 DOI: 10.1371/journal.pone.0099417] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 05/14/2014] [Indexed: 12/21/2022] Open
Abstract
The genus Sulfobacillus is a cohort of mildly thermophilic or thermotolerant acidophiles within the phylum Firmicutes and requires extremely acidic environments and hypersalinity for optimal growth. However, our understanding of them is still preliminary partly because few genome sequences are available. Here, the draft genome of Sulfobacillus thermosulfidooxidans strain ST was deciphered to obtain a comprehensive insight into the genetic content and to understand the cellular mechanisms necessary for its survival. Furthermore, the expressions of key genes related with iron and sulfur oxidation were verified by semi-quantitative RT-PCR analysis. The draft genome sequence of Sulfobacillus thermosulfidooxidans strain ST, which encodes 3225 predicted coding genes on a total length of 3,333,554 bp and a 48.35% G+C, revealed the high degree of heterogeneity with other Sulfobacillus species. The presence of numerous transposases, genomic islands and complete CRISPR/Cas defence systems testifies to its dynamic evolution consistent with the genome heterogeneity. As expected, S. thermosulfidooxidans encodes a suit of conserved enzymes required for the oxidation of inorganic sulfur compounds (ISCs). The model of sulfur oxidation in S. thermosulfidooxidans was proposed, which showed some different characteristics from the sulfur oxidation of Gram-negative A. ferrooxidans. Sulfur oxygenase reductase and heterodisulfide reductase were suggested to play important roles in the sulfur oxidation. Although the iron oxidation ability was observed, some key proteins cannot be identified in S. thermosulfidooxidans. Unexpectedly, a predicted sulfocyanin is proposed to transfer electrons in the iron oxidation. Furthermore, its carbon metabolism is rather flexible, can perform the transformation of pentose through the oxidative and non-oxidative pentose phosphate pathways and has the ability to take up small organic compounds. It encodes a multitude of heavy metal resistance systems to adapt the heavy metal-containing environments.
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Affiliation(s)
- Xue Guo
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Yili Liang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Qi Hu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xishu Zhou
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Yunhua Xiao
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Liyuan Ma
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Xian Zhang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Guanzhou Qiu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
- Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
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General Characteristics and Important Model Organisms. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2014. [DOI: 10.1128/9781555815516.ch2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lalli D, Turano P. Solution and solid state NMR approaches to draw iron pathways in the ferritin nanocage. Acc Chem Res 2013; 46:2676-85. [PMID: 24000809 DOI: 10.1021/ar4000983] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ferritins are intracellular proteins that can store thousands of iron(III) ions as a solid mineral. These structures autoassemble from four-helix bundle subunits to form a hollow sphere and are a prototypical example of protein nanocages. The protein acts as a reservoir, encapsulating iron as ferric oxide in its central cavity in a nontoxic and bioavailable form. Scientists have long known the structural details of the protein shell, owing to very high resolution X-ray structures of the apoform. However, the atomic level mechanism governing the multistep biomineralization process remained largely elusive. Through analysis of the chemical behavior of ferritin mutants, chemists have found the role of some residues in key reaction steps. Using Mössbauer and XAS, they have identified some di-iron intermediates of the catalytic reaction trapped by rapid freeze quench. However, structural information about the iron interaction sites remains scarce. The entire process is governed by a number of specific, but weak, interactions between the protein shell and the iron species moving across the cage. While this situation may constitute a major problem for crystallography, NMR spectroscopy represents an optimal tool to detect and characterize transient species involving soluble proteins. Regardless, NMR analysis of the 480 kDa ferritin represents a real challenge. Our interest in ferritin chemistry inspired us to use an original combination of solution and solid state approaches. While the highly symmetric structure of the homo-24-mer frog ferritin greatly simplifies the spectra, the large protein size hinders the efficient coherence transfer in solution, thus preventing the sequence specific assignments. In contrast, extensive (13)C-spin diffusion makes the solution (13)C-(13)C NOESY experiment our gold standard to monitor protein side chains both in the apoprotein alone and in its interaction with paramagnetic iron species, inducing line broadening on the resonances of nearby residues. We could retrieve the structural information embedded in the (13)C-(13)C NOESY due to a partial sequence specific assignment of protein backbone and side chains we obtained from solid state MAS NMR of ferritin microcrystals. We used the 59 assigned amino acids (∼33% of the total) as probes to locate paramagnetic ferric species in the protein cage. Through this approach, we could identify ferric dimers at the ferroxidase site and on their pathway towards the nanocage. Comparison with existing data on bacterioferritins and bacterial ferritins, as well as with eukaryotic ferritins loaded with various nonfunctional divalent ions, allowed us to reinterpret the available information. The resulting picture of the ferroxidase site is slightly different with various ferritins but is designed to provide multiple and generally weak iron ligands. The latter assist binding of two incoming iron(II) ions in two proximal positions to facilitate coupling with oxygen. Subsequent oxidation is accompanied by a decrease in the metal-metal distance (consistent with XAS/Mössbauer) and in the number of protein residues involved in metal coordination, facilitating the release of products as di-iron clusters under the effect of new incoming iron(II) ions.
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Affiliation(s)
- Daniela Lalli
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Paola Turano
- CERM and Department of Chemistry, University of Florence, via Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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Souness RJ, Kleffmann T, Tchesnokov EP, Wilbanks SM, Jameson GB, Jameson GNL. Mechanistic implications of persulfenate and persulfide binding in the active site of cysteine dioxygenase. Biochemistry 2013; 52:7606-17. [PMID: 24084026 DOI: 10.1021/bi400661a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Describing the organization of substrates and substrate analogues in the active site of cysteine dioxygenase identifies potential intermediates in this critical yet poorly understood reaction, the oxidation of cysteine to cysteine sulfinic acid. The fortuitous formation of persulfides under crystallization conditions has allowed their binding in the active site of cysteine dioxygenase to be studied. The crystal structures of cysteine persulfide and 3-mercaptopropionic acid persulfide bound to iron(II) in the active site show that binding of the persulfide occurs via the distal sulfide and, in the case of the cysteine persulfide, the amine also binds. Persulfide was detected by mass spectrometry in both the crystal and the drop, suggesting its origin is chemical rather than enzymatic. A mechanism involving the formation of the relevant disulfide from sulfide produced by hydrolysis of dithionite is proposed. In comparison, persulfenate {observed bound to cysteine dioxygenase [Simmons, C. R., et al. (2008) Biochemistry 47, 11390]} is shown through mass spectrometry to occur only in the crystal and not in the surrounding drop, suggesting that in the crystalline state the persulfenate does not lie on the reaction pathway. Stabilization of both the persulfenate and the persulfides does, however, suggest the position in which dioxygen binds during catalysis.
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Affiliation(s)
- Richard J Souness
- Department of Chemistry and MacDiarmid Institute for Advanced Materials and Nanotechnology and ‡Department of Biochemistry, University of Otago , P.O. Box 56, Dunedin 9054, New Zealand
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Abstract
Despite its reactivity and hence toxicity to living cells, sulfite is readily converted by various microorganisms using distinct assimilatory and dissimilatory metabolic routes. In respiratory pathways, sulfite either serves as a primary electron donor or terminal electron acceptor (yielding sulfate or sulfide, respectively), and its conversion drives electron transport chains that are coupled to chemiosmotic ATP synthesis. Notably, such processes are also seen to play a general role in sulfite detoxification, which is assumed to have an evolutionary ancient origin. The diversity of sulfite conversion is reflected by the fact that the range of microbial sulfite-converting enzymes displays different cofactors such as siroheme, heme c, or molybdopterin. This chapter aims to summarize the current knowledge of microbial sulfite metabolism and focuses on sulfite catabolism. The structure and function of sulfite-converting enzymes and the emerging picture of the modular architecture of the corresponding respiratory/detoxifying electron transport chains is emphasized.
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Affiliation(s)
- Jörg Simon
- Department of Biology, Microbial Energy Conversion and Biotechnology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.
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Site-specific mutagenesis and functional analysis of active sites of sulfur oxygenase reductase from Gram-positive moderate thermophile Sulfobacillus acidophilus TPY. Microbiol Res 2013; 168:654-60. [PMID: 23726793 DOI: 10.1016/j.micres.2013.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/03/2013] [Accepted: 04/13/2013] [Indexed: 11/23/2022]
Abstract
Sequence alignments revealed that the conserved motifs of SORSa which formed an independent branch between archaea and Gram-negative bacteria SORs according to the phylogenetic relationship were similar with the archaea and Gram-negative bacteria SORs. In order to investigate the active sites of SORSa, cysteines 31, 101 and 104 (C31, C101, C104), histidines 86 and 90 (H86 and H90) and glutamate 114 (E114) of SORSa were chosen as the target amino acid residues for site-specific mutagenesis. The wild type and six mutant SORs were expressed in E. coli BL21, purified and confirmed by SDS-PAGE and Western blotting analysis. Enzyme activity determination revealed that the active sites of SORSa were identical with the archaea and Gram-negative bacteria SORs reported. Replacement of any cysteine residues reduced SOR activity by 53-100%, while the mutants of H86A, H90A and E114A lost their enzyme activities largely, only remaining 20%, 19% and 32% activity of the wild type SOR respectively. This study will enrich our awareness for active sites of SOR in a Gram-positive bacterium.
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Bobadilla Fazzini RA, Cortés MP, Padilla L, Maturana D, Budinich M, Maass A, Parada P. Stoichiometric modeling of oxidation of reduced inorganic sulfur compounds (Riscs) in Acidithiobacillus thiooxidans. Biotechnol Bioeng 2013; 110:2242-51. [PMID: 23436458 DOI: 10.1002/bit.24875] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 02/07/2013] [Accepted: 02/11/2013] [Indexed: 11/09/2022]
Abstract
The prokaryotic oxidation of reduced inorganic sulfur compounds (RISCs) is a topic of utmost importance from a biogeochemical and industrial perspective. Despite sulfur oxidizing bacterial activity is largely known, no quantitative approaches to biological RISCs oxidation have been made, gathering all the complex abiotic and enzymatic stoichiometry involved. Even though in the case of neutrophilic bacteria such as Paracoccus and Beggiatoa species the RISCs oxidation systems are well described, there is a lack of knowledge for acidophilic microorganisms. Here, we present the first experimentally validated stoichiometric model able to assess RISCs oxidation quantitatively in Acidithiobacillus thiooxidans (strain DSM 17318), the archetype of the sulfur oxidizing acidophilic chemolithoautotrophs. This model was built based on literature and genomic analysis, considering a widespread mix of formerly proposed RISCs oxidation models combined and evaluated experimentally. Thiosulfate partial oxidation by the Sox system (SoxABXYZ) was placed as central step of sulfur oxidation model, along with abiotic reactions. This model was coupled with a detailed stoichiometry of biomass production, providing accurate bacterial growth predictions. In silico deletion/inactivation highlights the role of sulfur dioxygenase as the main catalyzer and a moderate function of tetrathionate hydrolase in elemental sulfur catabolism, demonstrating that this model constitutes an advanced instrument for the optimization of At. thiooxidans biomass production with potential use in biohydrometallurgical and environmental applications.
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Guiral M, Prunetti L, Aussignargues C, Ciaccafava A, Infossi P, Ilbert M, Lojou E, Giudici-Orticoni MT. The hyperthermophilic bacterium Aquifex aeolicus: from respiratory pathways to extremely resistant enzymes and biotechnological applications. Adv Microb Physiol 2013; 61:125-94. [PMID: 23046953 DOI: 10.1016/b978-0-12-394423-8.00004-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aquifex aeolicus isolated from a shallow submarine hydrothermal system belongs to the order Aquificales which constitute an important component of the microbial communities at elevated temperatures. This hyperthermophilic chemolithoautotrophic bacterium, which utilizes molecular hydrogen, molecular oxygen, and inorganic sulfur compounds to flourish, uses the reductive TCA cycle for CO(2) fixation. In this review, the intricate energy metabolism of A. aeolicus is described. As the chemistry of sulfur is complex and multiple sulfur species can be generated, A. aeolicus possesses a multitude of different enzymes related to the energy sulfur metabolism. It contains also membrane-embedded [NiFe] hydrogenases as well as oxidases enzymes involved in hydrogen and oxygen utilization. We have focused on some of these proteins that have been extensively studied and characterized as super-resistant enzymes with outstanding properties. We discuss the potential use of hydrogenases in an attractive H(2)/O(2) biofuel cell in replacement of chemical catalysts. Using complete genomic sequence and biochemical data, we present here a global view of the energy-generating mechanisms of A. aeolicus including sulfur compounds reduction and oxidation pathways as well as hydrogen and oxygen utilization.
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Affiliation(s)
- Marianne Guiral
- Unité de Bioénergétique et Ingénierie des Protéines, UMR7281-FR3479, CNRS, Aix-Marseille Université, Marseille, France.
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Abstract
Studies on sulfur metabolism in archaea have revealed many novel enzymes and pathways and have advanced our understanding on metabolic processes, not only of the archaea, but of biology in general. A variety of dissimilatory sulfur metabolisms, i.e. reactions used for energy conservation, are found in archaea from both the Crenarchaeota and Euryarchaeota phyla. Although not yet fully characterized, major processes include aerobic elemental sulfur (S(0)) oxidation, anaerobic S(0) reduction, anaerobic sulfate/sulfite reduction and anaerobic respiration of organic sulfur. Assimilatory sulfur metabolism, i.e. reactions used for biosynthesis of sulfur-containing compounds, also possesses some novel features. Cysteine biosynthesis in some archaea uses a unique tRNA-dependent pathway. Fe-S cluster biogenesis in many archaea differs from that in bacteria and eukaryotes and requires unidentified components. The eukaryotic ubiquitin system is conserved in archaea and involved in both protein degradation and biosynthesis of sulfur-containing cofactors. Lastly, specific pathways are utilized for the biosynthesis of coenzyme M and coenzyme B, the sulfur-containing cofactors required for methanogenesis.
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Affiliation(s)
- Yuchen Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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Aussignargues C, Giuliani MC, Infossi P, Lojou E, Guiral M, Giudici-Orticoni MT, Ilbert M. Rhodanese functions as sulfur supplier for key enzymes in sulfur energy metabolism. J Biol Chem 2012; 287:19936-48. [PMID: 22496367 DOI: 10.1074/jbc.m111.324863] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
How microorganisms obtain energy is a challenging topic, and there have been numerous studies on the mechanisms involved. Here, we focus on the energy substrate traffic in the hyperthermophilic bacterium Aquifex aeolicus. This bacterium can use insoluble sulfur as an energy substrate and has an intricate sulfur energy metabolism involving several sulfur-reducing and -oxidizing supercomplexes and enzymes. We demonstrate that the cytoplasmic rhodanese SbdP participates in this sulfur energy metabolism. Rhodaneses are a widespread family of proteins known to transfer sulfur atoms. We show that SbdP has also some unusual characteristics compared with other rhodaneses; it can load a long sulfur chain, and it can interact with more than one partner. Its partners (sulfur reductase and sulfur oxygenase reductase) are key enzymes of the sulfur energy metabolism of A. aeolicus and share the capacity to use long sulfur chains as substrate. We demonstrate a positive effect of SbdP, once loaded with sulfur chains, on sulfur reductase activity, most likely by optimizing substrate uptake. Taken together, these results lead us to propose a physiological role for SbdP as a carrier and sulfur chain donor to these key enzymes, therefore enabling channeling of sulfur substrate in the cell as well as greater efficiency of the sulfur energy metabolism of A. aeolicus.
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Affiliation(s)
- Clément Aussignargues
- Unité de Bioénergétique et Ingénierie des Protéines, Institut de Microbiologie de la Méditerranée-CNRS, Aix-Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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The sulfur oxygenase reductase from the mesophilic bacterium Halothiobacillus neapolitanus is a highly active thermozyme. J Bacteriol 2011; 194:677-85. [PMID: 22139503 DOI: 10.1128/jb.06531-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A biochemical, biophysical, and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties of the enzyme. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from Escherichia coli after heterologous gene expression had a temperature range of activity of 10 to 99°C with an optimum at 80°C (42 U/mg protein). Sulfite, thiosulfate, and hydrogen sulfide were formed at various stoichiometries in a range between pH 5.4 and 11 (optimum pH 8.4). Circular dichroism (CD) spectroscopy and dynamic light scattering showed that the HnSOR adopts secondary and quaternary structures similar to those of the 24-subunit enzyme from the hyperthermophile Acidianus ambivalens (AaSOR). The melting point of the HnSOR was ≈20°C lower than that of the AaSOR, when analyzed with CD-monitored thermal unfolding. Homology modeling showed that the secondary structure elements of single subunits are conserved. Subtle changes in the pores of the outer shell and increased flexibility might contribute to activity at low temperature. We concluded that the thermostability was the result of a rigid protein core together with the stabilizing effect of the 24-subunit hollow sphere.
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Cappadocia L, Parent JS, Zampini E, Lepage E, Sygusch J, Brisson N. A conserved lysine residue of plant Whirly proteins is necessary for higher order protein assembly and protection against DNA damage. Nucleic Acids Res 2011; 40:258-69. [PMID: 21911368 PMCID: PMC3245945 DOI: 10.1093/nar/gkr740] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
All organisms have evolved specialized DNA repair mechanisms in order to protect their genome against detrimental lesions such as DNA double-strand breaks. In plant organelles, these damages are repaired either through recombination or through a microhomology-mediated break-induced replication pathway. Whirly proteins are modulators of this second pathway in both chloroplasts and mitochondria. In this precise pathway, tetrameric Whirly proteins are believed to bind single-stranded DNA and prevent spurious annealing of resected DNA molecules with other regions in the genome. In this study, we add a new layer of complexity to this model by showing through atomic force microscopy that tetramers of the potato Whirly protein WHY2 further assemble into hexamers of tetramers, or 24-mers, upon binding long DNA molecules. This process depends on tetramer–tetramer interactions mediated by K67, a highly conserved residue among plant Whirly proteins. Mutation of this residue abolishes the formation of 24-mers without affecting the protein structure or the binding to short DNA molecules. Importantly, we show that an Arabidopsis Whirly protein mutated for this lysine is unable to rescue the sensitivity of a Whirly-less mutant plant to a DNA double-strand break inducing agent.
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Affiliation(s)
- Laurent Cappadocia
- Department of Biochemistry, Université de Montréal, CP 6128, Station Centre-Ville, Montréal H3C 3J7, Québec, Canada
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Reigstad LJ, Jorgensen SL, Lauritzen SE, Schleper C, Urich T. Sulfur-oxidizing chemolithotrophic proteobacteria dominate the microbiota in high arctic thermal springs on Svalbard. ASTROBIOLOGY 2011; 11:665-678. [PMID: 21899440 DOI: 10.1089/ast.2010.0551] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The thermal springs Trollosen and Fisosen, located on the High Arctic archipelago Svalbard, discharge saline groundwaters rich in hydrogen sulfide and ammonium through a thick layer of permafrost. Large amounts of biomass that consist of filamentous microorganisms containing sulfur granules, as analyzed with energy dispersive X-ray analysis, were found in the outflow. Prokaryotic 16S rRNA gene libraries and quantitative polymerase chain reaction (qPCR) analyses reported bacteria of the γ- and ɛ-proteobacterial classes as the dominant organisms in the filaments and the planktonic fractions, closely related to known chemolithoautotrophic sulfur oxidizers (Thiotrix and Sulfurovum). Archaea comprised ∼1% of the microbial community, with the majority of sequences affiliated with the Thaumarchaeota. Archaeal and bacterial genes coding for a subunit of the enzyme ammonia monooxygenase (amoA) were detected, as well as 16S rRNA genes of Nitrospira, all of which is indicative of potential complete nitrification in both springs. 16S rRNA sequences related to methanogens and methanotrophs were detected as well. This study provides evidence that the microbial communities in Trollosen and Fisosen are sustained by chemolithotrophy, mainly through the oxidation of reduced sulfur compounds, and that ammonium and methane might be minor, additional sources of energy and carbon.
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Veith A, Urich T, Seyfarth K, Protze J, Frazão C, Kletzin A. Substrate pathways and mechanisms of inhibition in the sulfur oxygenase reductase of acidianus ambivalens. Front Microbiol 2011; 2:37. [PMID: 21747782 PMCID: PMC3128934 DOI: 10.3389/fmicb.2011.00037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 02/17/2011] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The sulfur oxygenase reductase (SOR) is the initial enzyme of the sulfur oxidation pathway in the thermoacidophilic Archaeon Acidianus ambivalens. The SOR catalyzes an oxygen-dependent sulfur disproportionation to H(2)S, sulfite and thiosulfate. The spherical, hollow, cytoplasmic enzyme is composed of 24 identical subunits with an active site pocket each comprising a mononuclear non-heme iron site and a cysteine persulfide. Substrate access and product exit occur via apolar chimney-like protrusions at the fourfold symmetry axes, via narrow polar pores at the threefold symmetry axes and via narrow apolar pores within in each subunit. In order to investigate the function of the pores we performed site-directed mutagenesis and inhibitor studies. RESULTS Truncation of the chimney-like protrusions resulted in an up to sevenfold increase in specific enzyme activity compared to the wild type. Replacement of the salt bridge-forming Arg(99) residue by Ala at the threefold symmetry axes doubled the activity and introduced a bias toward reduced reaction products. Replacement of Met(296) and Met(297), which form the active site pore, lowered the specific activities by 25-55% with the exception of an M(296)V mutant. X-ray crystallography of SOR wild type crystals soaked with inhibitors showed that Hg(2+) and iodoacetamide (IAA) bind to cysteines within the active site, whereas Zn(2+) binds to a histidine in a side channel of the enzyme. The Zn(2+) inhibition was partially alleviated by mutation of the His residue. CONCLUSIONS The expansion of the pores in the outer shell led to an increased enzyme activity while the integrity of the active site pore seems to be important. Hg(2+) and IAA block cysteines in the active site pocket, while Zn(2+) interferes over a distance, possibly by restriction of protein flexibility or substrate access or product exit.
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Affiliation(s)
- Andreas Veith
- Institute of Microbiology and Genetics, Technische Universität DarmstadtDarmstadt, Germany
| | - Tim Urich
- Institute of Microbiology and Genetics, Technische Universität DarmstadtDarmstadt, Germany,Structural Biology Laboratory, Macromolecular Crystallography Unit, ITQB-UNLOeiras, Portugal
| | - Kerstin Seyfarth
- Institute of Microbiology and Genetics, Technische Universität DarmstadtDarmstadt, Germany
| | - Jonas Protze
- Institute of Microbiology and Genetics, Technische Universität DarmstadtDarmstadt, Germany
| | - Carlos Frazão
- Structural Biology Laboratory, Macromolecular Crystallography Unit, ITQB-UNLOeiras, Portugal
| | - Arnulf Kletzin
- Institute of Microbiology and Genetics, Technische Universität DarmstadtDarmstadt, Germany,*Correspondence: Arnulf Kletzin, Institute of Microbiology and Genetics, Technische Universität Darmstadt, Schnittspahnstraße 10, 64287 Darmstadt, Germany. e-mail:
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Mangold S, Valdés J, Holmes DS, Dopson M. Sulfur metabolism in the extreme acidophile acidithiobacillus caldus. Front Microbiol 2011; 2:17. [PMID: 21687411 PMCID: PMC3109338 DOI: 10.3389/fmicb.2011.00017] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/25/2011] [Indexed: 12/20/2022] Open
Abstract
Given the challenges to life at low pH, an analysis of inorganic sulfur compound (ISC) oxidation was initiated in the chemolithoautotrophic extremophile Acidithiobacillus caldus. A. caldus is able to metabolize elemental sulfur and a broad range of ISCs. It has been implicated in the production of environmentally damaging acidic solutions as well as participating in industrial bioleaching operations where it forms part of microbial consortia used for the recovery of metal ions. Based upon the recently published A. caldus type strain genome sequence, a bioinformatic reconstruction of elemental sulfur and ISC metabolism predicted genes included: sulfide-quinone reductase (sqr), tetrathionate hydrolase (tth), two sox gene clusters potentially involved in thiosulfate oxidation (soxABXYZ), sulfur oxygenase reductase (sor), and various electron transport components. RNA transcript profiles by semi quantitative reverse transcription PCR suggested up-regulation of sox genes in the presence of tetrathionate. Extensive gel based proteomic comparisons of total soluble and membrane enriched protein fractions during growth on elemental sulfur and tetrathionate identified differential protein levels from the two Sox clusters as well as several chaperone and stress proteins up-regulated in the presence of elemental sulfur. Proteomics results also suggested the involvement of heterodisulfide reductase (HdrABC) in A. caldus ISC metabolism. A putative new function of Hdr in acidophiles is discussed. Additional proteomic analysis evaluated protein expression differences between cells grown attached to solid, elemental sulfur versus planktonic cells. This study has provided insights into sulfur metabolism of this acidophilic chemolithotroph and gene expression during attachment to solid elemental sulfur.
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Affiliation(s)
| | - Jorge Valdés
- Center for Bioinformatics and Genome Biology, Fundación Ciencia para VidaSantiago, Chile
| | - David S. Holmes
- Center for Bioinformatics and Genome Biology, Fundación Ciencia para VidaSantiago, Chile
- Departamento de Ciencias Biologicas, Andrés Bello UniversitySantiago, Chile
| | - Mark Dopson
- Center for Bioinformatics and Genome Biology, Fundación Ciencia para VidaSantiago, Chile
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41
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Grocholski T, Koskiniemi H, Lindqvist Y, Mäntsälä P, Niemi J, Schneider G. Crystal structure of the cofactor-independent monooxygenase SnoaB from Streptomyces nogalater: implications for the reaction mechanism. Biochemistry 2010; 49:934-44. [PMID: 20052967 DOI: 10.1021/bi901985b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
SnoaB is a cofactor-independent monooxygenase that catalyzes the conversion of 12-deoxynogalonic acid to nogalonic acid in the biosynthesis of the aromatic polyketide nogalamycin in Streptomyces nogalater. In vitro (18)O(2) experiments establish that the oxygen atom incorporated into the substrate is derived from molecular oxygen. The crystal structure of the enzyme was determined in two different space groups to 1.7 and 1.9 A resolution, respectively. The enzyme displays the ferredoxin fold, with the characteristic beta-strand exchange at the dimer interface. The crystal structures reveal a putative catalytic triad involving two asparagine residues, Asn18 and Asn63, and a water molecule, which may play important roles in the enzymatic reaction. Site-directed mutagenesis experiments, replacing the two asparagines individually by alanine, led to a 100-fold drop in enzymatic activity. Replacement of an invariant tryptophan residue in the active site of the enzyme by phenylalanine also resulted in an enzyme variant with about 1% residual activity. Taken together, our findings are most consistent with a carbanion mechanism where the deprotonated substrate reacts with molecular oxygen via one electron transfer and formation of a caged radical.
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Affiliation(s)
- Thadee Grocholski
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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42
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Ghosh W, Dam B. Biochemistry and molecular biology of lithotrophic sulfur oxidation by taxonomically and ecologically diverse bacteria and archaea. FEMS Microbiol Rev 2009; 33:999-1043. [PMID: 19645821 DOI: 10.1111/j.1574-6976.2009.00187.x] [Citation(s) in RCA: 288] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Lithotrophic sulfur oxidation is an ancient metabolic process. Ecologically and taxonomically diverged prokaryotes have differential abilities to utilize different reduced sulfur compounds as lithotrophic substrates. Different phototrophic or chemotrophic species use different enzymes, pathways and mechanisms of electron transport and energy conservation for the oxidation of any given substrate. While the mechanisms of sulfur oxidation in obligately chemolithotrophic bacteria, predominantly belonging to Beta- (e.g. Thiobacillus) and Gammaproteobacteria (e.g. Thiomicrospira), are not well established, the Sox system is the central pathway in the facultative bacteria from Alphaproteobacteria (e.g. Paracoccus). Interestingly, photolithotrophs such as Rhodovulum belonging to Alphaproteobacteria also use the Sox system, whereas those from Chromatiaceae and Chlorobi use a truncated Sox complex alongside reverse-acting sulfate-reducing systems. Certain chemotrophic magnetotactic Alphaproteobacteria allegedly utilize such a combined mechanism. Sulfur-chemolithotrophic metabolism in Archaea, largely restricted to Sulfolobales, is distinct from those in Bacteria. Phylogenetic and biomolecular fossil data suggest that the ubiquity of sox genes could be due to horizontal transfer, and coupled sulfate reduction/sulfide oxidation pathways, originating in planktonic ancestors of Chromatiaceae or Chlorobi, could be ancestral to all sulfur-lithotrophic processes. However, the possibility that chemolithotrophy, originating in deep sea, is the actual ancestral form of sulfur oxidation cannot be ruled out.
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Affiliation(s)
- Wriddhiman Ghosh
- Department of Microbiology, University of Burdwan, West Bengal, India.
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43
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Abstract
The elemental sulfur oxidising enzyme Sulfur Oxygenase Reductase (SOR) is very well investigated in acidothermophilic archaea, such as Acidianus brierleyi and Sulfolobus metallicus. In contrast, not much is known about the biochemistry of elemental sulfur oxidation in acidophilic bacteria. Recently, however, the SOR-encoding gene has been found also in a bacterial strain closely related to the moderate thermophile Acidithiobacillus caldus. Confusingly, for the latter species, also the involvement of the SOX system as well as thiosulfate:quinone oxidoreductase (TQO) and tetrathionate hydrolase (TTH) in sulfur compound oxidation has been proposed based on genome analysis. In this study, we have detected the sor-gene in other Acidithiobacillus caldus-like strains, isolated from various bioleaching habitats, indicating that SOR plays an important role in sulfur oxidation in this species. Based on sequence comparison, the new bacterial sor-genes are closely related and distant from the known archaeal sequences as well as from the SOR found in the neutrophilic bacterium Aquifex aeolicus. In addition, SOR activity has been detected in crude cell extracts from all Acidithiobacillus caldus-like strains tested. The enzyme is truly thermophilic as highest activities were achieved at 65 °C, which is far beyond the growth optimum of Acidithiobacillus caldus. This finding may give rise to the question whether the presence of SOR in Acidithiobacillus caldus is only relevant while growing at elevated temperatures. Currently, experiments are performed for testing this hypothesis (comparing growth and enzyme activities at 30 vs. 45 °C).
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44
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Andreini C, Bertini I, Cavallaro G, Najmanovich RJ, Thornton JM. Structural analysis of metal sites in proteins: non-heme iron sites as a case study. J Mol Biol 2009; 388:356-80. [PMID: 19265704 DOI: 10.1016/j.jmb.2009.02.052] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 11/24/2022]
Abstract
In metalloproteins, the protein environment modulates metal properties to achieve the required goal, which can be protein stabilization or function. The analysis of metal sites at the atomic level of detail provided by protein structures can thus be of benefit in functional and evolutionary studies of proteins. In this work, we propose a structural bioinformatics approach to the study of metalloproteins based on structural templates of metal sites that include the PDB coordinates of protein residues forming the first and the second coordination sphere of the metal. We have applied this approach to non-heme iron sites, which have been analyzed at various levels. Templates of sites located in different protein domains have been compared, showing that similar sites can be found in unrelated proteins as the result of convergent evolution. Templates of sites located in proteins of a large superfamily have been compared, showing possible mechanisms of divergent evolution of proteins to achieve different functions. Furthermore, template comparisons have been used to predict the function of uncharacterized proteins, showing that similarity searches focused on metal sites can be advantageously combined with typical whole-domain comparisons. Structural templates of metal sites, finally, may constitute the basis for a systematic classification of metalloproteins in databases.
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Affiliation(s)
- Claudia Andreini
- Magnetic Resonance Center (CERM)-University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
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45
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Abstract
Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative of the Chromatiaceae), and many are well characterized also on a molecular genetic level. Complete genome sequence data are currently available for 10 strains of GSB and for one strain of PSB. We present here a genome-based survey of the distribution and phylogenies of genes involved in oxidation of sulfur compounds in these strains. It is evident from biochemical and genetic analyses that the dissimilatory sulfur metabolism of these organisms is very complex and incompletely understood. This metabolism is modular in the sense that individual steps in the metabolism may be performed by different enzymes in different organisms. Despite the distant evolutionary relationship between GSB and PSB, their photosynthetic nature and their dependency on oxidation of sulfur compounds resulted in similar ecological roles in the sulfur cycle as important anaerobic oxidizers of sulfur compounds.
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Auernik KS, Cooper CR, Kelly RM. Life in hot acid: pathway analyses in extremely thermoacidophilic archaea. Curr Opin Biotechnol 2008; 19:445-53. [PMID: 18760359 DOI: 10.1016/j.copbio.2008.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 07/24/2008] [Accepted: 08/01/2008] [Indexed: 02/08/2023]
Abstract
The extremely thermoacidophilic archaea are a particularly intriguing group of microorganisms that must simultaneously cope with biologically extreme pHs (< or = 4) and temperatures (Topt > or = 60 degrees C) in their natural environments. Their expanding biotechnological significance relates to their role in biomining of base and precious metals and their unique mechanisms of survival in hot acid, at both the cellular and biomolecular levels. Recent developments, such as advances in understanding of heavy metal tolerance mechanisms, implementation of a genetic system, and discovery of a new carbon fixation pathway, have been facilitated by the availability of genome sequence data and molecular genetic systems. As a result, new insights into the metabolic pathways and physiological features that define extreme thermoacidophily have been obtained, in some cases suggesting prospects for biotechnological opportunities.
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Affiliation(s)
- Kathryne S Auernik
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA
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X-ray absorption spectroscopy as a probe of microbial sulfur biochemistry: the nature of bacterial sulfur globules revisited. J Bacteriol 2008; 190:6376-83. [PMID: 18676668 DOI: 10.1128/jb.00539-08] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chemical nature of the sulfur in bacterial sulfur globules has been the subject of controversy for a number of years. Sulfur K-edge X-ray absorption spectroscopy (XAS) is a powerful technique for probing the chemical forms of sulfur in situ, but two groups have used it with very different conclusions. The root of the controversy lies with the different detection strategies used by the two groups, which result in very different spectra. This paper seeks to resolve the controversy. We experimentally demonstrate that the use of transmittance detection for sulfur K-edge XAS measurements is highly prone to spectroscopic distortions and that much of the published work on sulfur bacteria is very likely based on distorted data. We also demonstrate that all three detection methods used for X-ray absorption experiments yield essentially identical spectra when the measurements are carried out under conditions where no experimental distortions are expected. Finally, we turn to the original question--the chemical nature of bacterial sulfur. We examine isolated sulfur globules of Allochromatium vinosum and intact cells of a strain of magnetotactic coccus and show that XAS indicates the presence of a chemical form of sulfur resembling S(8).
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48
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Biochemistry and molecular biology in Portugal: An overview of past and current contributions. IUBMB Life 2008; 60:265-9. [DOI: 10.1002/iub.65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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49
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Crystal structure studies on sulfur oxygenase reductase from Acidianus tengchongensis. Biochem Biophys Res Commun 2008; 369:919-23. [PMID: 18329378 DOI: 10.1016/j.bbrc.2008.02.131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 02/26/2008] [Indexed: 11/21/2022]
Abstract
Sulfur oxygenase reductase (SOR) simultaneously catalyzes oxidation and reduction of elemental sulfur to produce sulfite, thiosulfate, and sulfide in the presence of molecular oxygen. In this study, crystal structures of wild type and mutants of SOR from Acidianus tengchongensis (SOR-AT) in two different crystal forms were determined and it was observed that 24 identical SOR monomers form a hollow sphere. Within the icosatetramer sphere, the tetramer and trimer channels were proposed as the paths for the substrate and products, respectively. Moreover, a comparison of SOR-AT with SOR-AA (SOR from Acidianus ambivalens) structures showed that significant differences existed at the active site. Firstly, Cys31 is not persulfurated in SOR-AT structures. Secondly, the iron atom is five-coordinated rather than six-coordinated, since one of the water molecules ligated to the iron atom in the SOR-AA structure is lost. Consequently, the binding sites of substrates and a hypothetical catalytic process of SOR were proposed.
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50
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Bruijnincx PCA, van Koten G, Klein Gebbink RJM. Mononuclear non-heme iron enzymes with the 2-His-1-carboxylate facial triad: recent developments in enzymology and modeling studies. Chem Soc Rev 2008; 37:2716-44. [DOI: 10.1039/b707179p] [Citation(s) in RCA: 412] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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