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Guo Y, Karimullina E, Emde T, Otwinowski Z, Borek D, Savchenko A. Monomer and dimer structures of cytochrome bo 3 ubiquinol oxidase from Escherichia coli. Protein Sci 2023; 32:e4616. [PMID: 36880269 PMCID: PMC10037687 DOI: 10.1002/pro.4616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023]
Abstract
The E. coli cytochrome bo3 ubiquinol oxidase is a four-subunit heme-copper oxidase that serves as a proton pump in the E. coli aerobic respiratory chain. Despite many mechanistic studies, it is unclear whether this ubiquinol oxidase functions as a monomer, or as a dimer in a manner similar to its eukaryotic counterparts - the mitochondrial electron transport complexes. In this study, we determined the monomeric and dimeric structures of the E. coli cytochrome bo3 ubiquinol oxidase reconstituted in amphipol by cryogenic electron microscopy single particle reconstruction (cryo-EM SPR) to a resolution of 3.15 Å and 3.46 Å, respectively. We have discovered that the protein can form a dimer with C2 symmetry, with the dimerization interface maintained by interactions between the subunit II of one monomer and the subunit IV of the other monomer. Moreover, the dimerization does not induce significant structural changes in the monomers, except the movement of a loop in subunit IV (residues 67-74). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yirui Guo
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
- Ligo Analytics, 2207 Chunk Ct, Dallas, Texas, United States
| | - Elina Karimullina
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, Illinois, USA
- Centers for Research on Structural Biology of Infectious Diseases (CSBID), Chicago, Illinois, USA
| | - Tabitha Emde
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, Illinois, USA
- Centers for Research on Structural Biology of Infectious Diseases (CSBID), Chicago, Illinois, USA
| | - Zbyszek Otwinowski
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, Illinois, USA
- Centers for Research on Structural Biology of Infectious Diseases (CSBID), Chicago, Illinois, USA
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
| | - Dominika Borek
- Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, Illinois, USA
- Centers for Research on Structural Biology of Infectious Diseases (CSBID), Chicago, Illinois, USA
- Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, Texas, US
| | - Alexei Savchenko
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), Chicago, Illinois, USA
- Centers for Research on Structural Biology of Infectious Diseases (CSBID), Chicago, Illinois, USA
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
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Klint H, Lejonklou MH, Karimullina E, Rönn M, Lind L, Lind PM, Brittebo E. Low-dose exposure to bisphenol A in combination with fructose increases expression of genes regulating angiogenesis and vascular tone in juvenile Fischer 344 rat cardiac tissue. Ups J Med Sci 2017; 122:20-27. [PMID: 27622962 PMCID: PMC5361428 DOI: 10.1080/03009734.2016.1225870] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/08/2016] [Accepted: 08/15/2016] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES Epidemiological studies report associations between exposure to the high-volume chemical and endocrine disruptor bisphenol A (BPA) and cardiovascular disorders, but there is a lack of experimental studies addressing the mechanisms of action of BPA on the cardiovascular system. In the present study, effects on markers for cardiovascular function of exposure to BPA and fructose in vivo in rat cardiac tissues, and of BPA exposure in human cardiomyocytes in vitro, were investigated. MATERIALS Juvenile female Fischer 344 rats were exposed to 5, 50, and 500 μg BPA/kg bodyweight/day in their drinking water from 5 to 15 weeks of age, in combination with 5% fructose. Further, cultured human cardiomyocytes were exposed to 10 nM BPA to 1 × 104 nM BPA for six hours. Expression of markers for cardiovascular function and BPA target receptors was investigated using qRT-PCR. RESULTS Exposure to 5 μg BPA/kg bodyweight/day plus fructose increased mRNA expression of Vegf, Vegfr2, eNos, and Ace1 in rat heart. Exposure of human cardiomyocytes to 1 × 104 nM BPA increased mRNA expression of eNOS and ACE1, as well as IL-8 and NFκβ known to regulate inflammatory response. CONCLUSIONS . Low-dose exposure of juvenile rats to BPA and fructose induced up-regulation of expression of genes controlling angiogenesis and vascular tone in cardiac tissues. The observed effects of BPA in rat heart were in line with our present and previous studies of BPA in human endothelial cells and cardiomyocytes. These findings may aid in understanding the mechanisms of the association between BPA exposure and cardiovascular disorders reported in epidemiological studies.
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Affiliation(s)
- Helén Klint
- Uppsala University, Department of Pharmaceutical Biosciences, SE-75124 Uppsala, Sweden
| | | | - Elina Karimullina
- University of California, Irvine, Department of Developmental and Cell Biology, Irvine, CA 92697, USA
| | - Monika Rönn
- Uppsala University, Department of Medical Sciences, SE-75185 Uppsala, Sweden
| | - Lars Lind
- Uppsala University, Department of Medical Sciences, SE-75185 Uppsala, Sweden
| | - P. Monica Lind
- Uppsala University, Department of Medical Sciences, SE-75185 Uppsala, Sweden
| | - Eva Brittebo
- Uppsala University, Department of Pharmaceutical Biosciences, SE-75124 Uppsala, Sweden
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Karimullina E, Antonova EV, Pozolotina VN. Genetic variation in natural Melandrium album populations exposed to chronic ionizing radiation. Environ Sci Pollut Res Int 2016; 23:21565-21576. [PMID: 27515527 DOI: 10.1007/s11356-016-7355-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
The effect of radiation pollution on genetic variation in natural populations of Melandrium album was investigated at the head part of the East-Ural Radioactive Trace (EURT) and background areas. The highest genetic differentiation estimated using F ST was revealed between compared pairs of the background and impact samples in populations of M. album. The highest rate of polymorphism was observed at the closest to nuclear accident, Impact-1 site. The unique alleles (Mdh-3104, Pgi-2106, Lap 105, Mdh-296, and Dia 94) were discovered at the EURT. Individuals from chronically low-level irradiated sites were genetically closer than to plants from background sites using Nadhdh locus. The increase of the frequency of unique homozygous and heterozygous genotypes was identified in populations of M. album growing under chronic radiation exposure conditions. The largest contribution to the group of unique heterozygous genotypes at the EURT was made by three loci - Lap, Pgi-2, and Nadhdh; the main role in interpopulation differentiation of samples was made by the alleles Sod-2115, Skdh 100, and Nadhdh 100. Our results provide evidence for the correlation between the increase of genetic variation other than the «genetic erosion» and chronic radiation exposure factor in natural plant populations.
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Affiliation(s)
- Elina Karimullina
- Laboratory of Population Radiobiology, Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, 8 Marta St., 202, Ekaterinburg, Russian Federation, 620144.
| | - Elena V Antonova
- Laboratory of Population Radiobiology, Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, 8 Marta St., 202, Ekaterinburg, Russian Federation, 620144
| | - Vera N Pozolotina
- Laboratory of Population Radiobiology, Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, 8 Marta St., 202, Ekaterinburg, Russian Federation, 620144
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Karimullina E, Antonova E, Pozolotina V. Assessing radiation exposure of herbaceous plant species at the East-Ural Radioactive Trace. J Environ Radioact 2013; 124:113-120. [PMID: 23694686 DOI: 10.1016/j.jenvrad.2013.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 04/05/2013] [Accepted: 04/12/2013] [Indexed: 06/02/2023]
Abstract
The East-Ural Radioactive Trace (EURT) is a result of the Mayak Production Association accident that occurred in 1957 in Russia. Radiological assessment improves the interpretation of biological effects of exposure to ionizing radiation. Therefore a modeling approach was used to estimate dose rates on Leonurus quinquelobatus, Silene latifolia, Stellaria graminea and Bromus inermis. Soil-to-organism transfer parameter values are delivered from empirical data of (90)Sr and (137)Cs soil and vegetative plant mass activity concentrations. External and internal whole-body dose rates were calculated using deterministic (The ERICA Tool-Tier 2 and R&D 128/SP1a) and probabilistic (The ERICA Tool-Tier 3) methods. The total dose rate for herbs was under 100 μGy h(-1) at the most polluted site. The total absorbed dose rates increased 43-110 times (Tier 3) for different herbaceous plant species along the pollution gradient. Based on these data, it can be concluded that herbaceous plant populations currently exist under low-level chronic exposure at the EURT area.
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Affiliation(s)
- Elina Karimullina
- Institute of Plant & Animal Ecology, Ural Branch, Russian Academy of Sciences, 8 Marta, 202, Yekaterinburg 620144, Russian Federation.
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Karimullina E, Li Y, Ginjupalli G, Baldwin WS. Daphnia HR96 is a promiscuous xenobiotic and endobiotic nuclear receptor. Aquat Toxicol 2012; 116-117:69-78. [PMID: 22466357 PMCID: PMC3334431 DOI: 10.1016/j.aquatox.2012.03.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 03/02/2012] [Accepted: 03/06/2012] [Indexed: 05/20/2023]
Abstract
Daphnia pulex is the first crustacean to have its genome sequenced. The genome project provides new insight and data into how an aquatic crustacean may respond to environmental stressors, including toxicants. We cloned Daphnia pulex HR96 (DappuHR96), a nuclear receptor orthologous to the CAR/PXR/VDR group of nuclear receptors. In Drosophila melanogaster, (hormone receptor 96) HR96 responds to phenobarbital exposure and has been hypothesized as a toxicant receptor. Therefore, we set up a transactivation assay to test whether DappuHR96 is a promiscuous receptor activated by xenobiotics and endobiotics similar to the constitutive androstane receptor (CAR) and the pregnane X-receptor (PXR). Transactivation assays performed with a GAL4-HR96 chimera demonstrate that HR96 is a promiscuous toxicant receptor activated by a diverse set of chemicals such as pesticides, hormones, and fatty acids. Several environmental toxicants activate HR96 including estradiol, pyriproxyfen, chlorpyrifos, atrazine, and methane arsonate. We also observed repression of HR96 activity by chemicals such as triclosan, androstanol, and fluoxetine. Nearly 50% of the chemicals tested activated or inhibited HR96. Interestingly, unsaturated fatty acids were common activators or inhibitors of HR96 activity, indicating a link between diet and toxicant response. The omega-6 and omega-9 unsaturated fatty acids linoleic and oleic acid activated HR96, but the omega-3 unsaturated fatty acids alpha-linolenic acid and docosahexaenoic acid inhibited HR96, suggesting that these two distinct sets of lipids perform opposing roles in Daphnia physiology. This also provides a putative mechanism by which the ratio of dietary unsaturated fats may affect the ability of an organism to respond to a toxic insult. In summary, HR96 is a promiscuous nuclear receptor activated by numerous endo- and xenobiotics.
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Affiliation(s)
- Elina Karimullina
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
- Institute of Plant & Animal Ecology, Russian Academy of Sciences, Ural Branch, Yekaterinburg, Russia 620144
- Fullbright Foundation Post-graduate Fellow
| | - Yangchun Li
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
| | - Gautam Ginjupalli
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
| | - William S. Baldwin
- Environmental Toxicology Program, Clemson University, Clemson, SC, USA 29634
- Biological Sciences, Clemson University, Clemson, SC, USA
- To Whom Correspondence Should Be Addressed: William S. Baldwin, Clemson University, Biological Sciences, 132 Long Hall, Clemson, SC 29634, 864-656-2340,
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