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Zhan T, Jacoby C, Jede M, Knapp B, Ferlaino S, Günter A, Drepper F, Müller M, Weber S, Boll M. Bacterial stigmasterol degradation involving radical flavin delta-24 desaturase and molybdenum-dependent C26 hydroxylase. J Biol Chem 2024; 300:107243. [PMID: 38556086 PMCID: PMC11061730 DOI: 10.1016/j.jbc.2024.107243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 03/20/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024] Open
Abstract
Sterols are ubiquitous membrane constituents that persist to a large extent in the environment due to their water insolubility and chemical inertness. Recently, an oxygenase-independent sterol degradation pathway was discovered in a cholesterol-grown denitrifying bacterium Sterolibacterium (S.) denitrificans. It achieves hydroxylation of the unactivated primary C26 of the isoprenoid side chain to an allylic alcohol via a phosphorylated intermediate in a four-step ATP-dependent enzyme cascade. However, this pathway is incompatible with the degradation of widely distributed steroids containing a double bond at C22 in the isoprenoid side chain such as the plant sterol stigmasterol. Here, we have enriched a prototypical delta-24 desaturase from S. denitrificans, which catalyzes the electron acceptor-dependent oxidation of the intermediate stigmast-1,4-diene-3-one to a conjugated (22,24)-diene. We suggest an α4β4 architecture of the 440 kDa enzyme, with each subunit covalently binding an flavin mononucleotide cofactor to a histidyl residue. As isolated, both flavins are present as red semiquinone radicals, which can be reduced by stigmast-1,4-diene-3-one but cannot be oxidized even with strong oxidizing agents. We propose a mechanism involving an allylic radical intermediate in which two flavin semiquinones each abstract one hydrogen atom from the substrate. The conjugated delta-22,24 moiety formed allows for the subsequent hydroxylation of the terminal C26 with water by a heterologously produced molybdenum-dependent steroid C26 dehydrogenase 2. In conclusion, the pathway elucidated for delta-22 steroids achieves oxygen-independent hydroxylation of the isoprenoid side chain by bypassing the ATP-dependent formation of a phosphorylated intermediate.
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Affiliation(s)
- Tingyi Zhan
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Christian Jacoby
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Martin Jede
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany
| | - Bettina Knapp
- Faculty of Biology, Department of Biochemistry and Functional Proteomics, University of Freiburg, Freiburg, Germany
| | - Sascha Ferlaino
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Andreas Günter
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
| | - Friedel Drepper
- Faculty of Biology, Department of Biochemistry and Functional Proteomics, University of Freiburg, Freiburg, Germany
| | - Michael Müller
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany
| | - Stefan Weber
- Institute of Physical Chemistry, University of Freiburg, Freiburg, Germany
| | - Matthias Boll
- Faculty of Biology, Department of Microbiology, University of Freiburg, Freiburg, Germany.
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Barroso GC, Abril G, Machado W, Abuchacra RC, Peixoto RB, Bernardes M, Marques GS, Sanders CJ, Oliveira GB, Oliveira Filho SR, Amora-Nogueira L, Marotta H. Linking eutrophication to carbon dioxide and methane emissions from exposed mangrove soils along an urban gradient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 850:157988. [PMID: 35963403 DOI: 10.1016/j.scitotenv.2022.157988] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 07/22/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Mangroves are one of the most important but threatened blue carbon ecosystems globally. Rapid urban growth has resulted in nutrient inputs and subsequent coastal eutrophication, associated with an enrichment in organic matter (OM) from algal and sewage sources and substantial changes in greenhouse gas (GHG) emissions. However, the effects of nitrogen (N) and phosphorus (P) enrichment on mangrove soil OM composition and GHG emissions, such as methane (CH4) and carbon dioxide (CO2), are still poorly understood. Here, we aim to evaluate the relationships between CO2 and CH4 efflux with OM composition in exposed soils from three mangrove areas along watersheds with different urbanization levels (Rio de Janeiro State, Brazil). To assess spatial (lower vs. upper intertidal zones) and seasonal (summer vs. winter) variability, we measured soil-air CO2 and CH4 fluxes at low spring tide, analyzing elementary (C, N, and P), isotopic (δ13C and δ15N), and the molecular (n-alkanes and sterols) composition of surface soil OM. A general trend of OM composition was found with increasing urban influence, with higher δ15N (proxy of anthropogenic N enrichment), less negative δ13C, more short-chain n-alkanes, lower C:N ratio (proxies of algal biomass), and higher epicoprostanol content (proxies of sewage-derived OM). The CO2 efflux from exposed soils increased greatly in median (25/75 % interquartile range) from 4.6 (2.9/8.3) to 24.0 (21.5/32.7) mmol m-2 h-1 from more pristine to more urbanized watersheds, independent of intertidal zone and seasonality. The CO2 fluxes at the most eutrophicated site were among the highest reported worldwide for mangrove soils. Conversely, CH4 emissions were relatively low (three orders of magnitude lower than CO2 fluxes), with high peaks in the lower intertidal zone during the rainy summer. Thus, our findings demonstrate the influence of coastal eutrophication on global warming potentials related to enhanced heterotrophic remineralization of blue carbon within mangrove soils.
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Affiliation(s)
- Glenda C Barroso
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil
| | - Gwenaël Abril
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Laboratoire de Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), FRE 2020, Muséum National d'Histoire Naturelle, CNRS, IRD, SU, UCN, UA, Paris, France
| | - Wilson Machado
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil
| | - Rodrigo C Abuchacra
- Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil; Department of Geography, Graduate Program in Geography, State University of Rio de Janeiro (UERJ/FFP), Rua Dr. Francisco Portela, 1470 São Gonçalo, 24435-005 Rio de Janeiro, Brazil
| | - Roberta B Peixoto
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil
| | - Marcelo Bernardes
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil
| | - Gabriela S Marques
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil
| | - Christian J Sanders
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour, NSW 2540, Australia
| | - Gabriela B Oliveira
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil
| | - Silvio R Oliveira Filho
- Physical Geography Laboratory (LAGEF-UFF), Department of Geography, Graduate Program in Geography, Fluminense Federal University (UFF), Av. Gal. Milton Tavares de Souza, s/n°, Niterói, RJ 24210-346, Brazil
| | - Leonardo Amora-Nogueira
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil; Physical Geography Laboratory (LAGEF-UFF), Department of Geography, Graduate Program in Geography, Fluminense Federal University (UFF), Av. Gal. Milton Tavares de Souza, s/n°, Niterói, RJ 24210-346, Brazil
| | - Humberto Marotta
- Graduate Program in Geosciences (Environmental Geochemistry), Fluminense Federal University (UFF), Outeiro São João Baptista, s/n, 24020-007 Niterói, Brazil; Ecosystems and Global Change Laboratory (LEMG-UFF)/Brazilian Ocean Acidification Network (BrOA), International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Fluminense Federal University (UFF), Av. Edmundo March, s/n°, Niterói, RJ 24210-310, Brazil; Physical Geography Laboratory (LAGEF-UFF), Department of Geography, Graduate Program in Geography, Fluminense Federal University (UFF), Av. Gal. Milton Tavares de Souza, s/n°, Niterói, RJ 24210-346, Brazil.
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Hargrove TY, Lamb DC, Smith JA, Wawrzak Z, Kelly SL, Lepesheva GI. Unravelling the role of transient redox partner complexes in P450 electron transfer mechanics. Sci Rep 2022; 12:16232. [PMID: 36171457 PMCID: PMC9519919 DOI: 10.1038/s41598-022-20671-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/16/2022] [Indexed: 01/05/2023] Open
Abstract
The molecular evolution of cytochromes P450 and associated redox-driven oxidative catalysis remains a mystery in biology. It is widely believed that sterol 14α-demethylase (CYP51), an essential enzyme of sterol biosynthesis, is the ancestor of the whole P450 superfamily given its conservation across species in different biological kingdoms. Herein we have utilized X-ray crystallography, molecular dynamics simulations, phylogenetics and electron transfer measurements to interrogate the nature of P450-redox partner binding using the naturally occurring fusion protein, CYP51-ferredoxin found in the sterol-producing bacterium Methylococcus capsulatus. Our data advocates that the electron transfer mechanics in the M. capsulatus CYP51-ferredoxin fusion protein involves an ensemble of ferredoxin molecules in various orientations and the interactions are transient. Close proximity of ferredoxin, however, is required to complete the substrate-induced large-scale structural switch in the P450 domain that enables proton-coupled electron transfer and subsequent oxygen scission and catalysis. These results have fundamental implications regarding the early evolution of electron transfer proteins and for the redox reactions in the early steps of sterol biosynthesis. They also shed new light on redox protein mechanics and the subsequent diversification of the P450 electron transfer machinery in nature.
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Affiliation(s)
- Tatiana Y Hargrove
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - David C Lamb
- Faculty of Medicine, Health and Life Science, Swansea University, Swansea, SA2 8PP, UK
| | - Jarrod A Smith
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA.,Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, IL, 60439, USA
| | - Steven L Kelly
- Faculty of Medicine, Health and Life Science, Swansea University, Swansea, SA2 8PP, UK
| | - Galina I Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA. .,Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA.
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4
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Carreón-Palau L, Özdemir NŞ, Parrish CC, Parzanini C. Sterol Composition of Sponges, Cnidarians, Arthropods, Mollusks, and Echinoderms from the Deep Northwest Atlantic: A Comparison with Shallow Coastal Gulf of Mexico. Mar Drugs 2020; 18:md18120598. [PMID: 33260983 PMCID: PMC7761341 DOI: 10.3390/md18120598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 01/31/2023] Open
Abstract
Triterpenoid biosynthesis is generally anaerobic in bacteria and aerobic in Eukarya. The major class of triterpenoids in bacteria, the hopanoids, is different to that in Eukarya, the lanostanoids, and their 4,4,14-demethylated derivatives, sterols. In the deep sea, the prokaryotic contribution to primary productivity has been suggested to be higher because local environmental conditions prevent classic photosynthetic processes from occurring. Sterols have been used as trophic biomarkers because primary producers have different compositions, and they are incorporated in primary consumer tissues. In the present study, we inferred food supply to deep sea, sponges, cnidarians, mollusks, crustaceans, and echinoderms from euphotic zone production which is driven by phytoplankton eukaryotic autotrophy. Sterol composition was obtained by gas chromatography and mass spectrometry. Moreover, we compared the sterol composition of three phyla (i.e., Porifera, Cnidaria, and Echinodermata) collected between a deep and cold-water region and a shallow tropical area. We hypothesized that the sterol composition of shallow tropical benthic organisms would better reflect their photoautotrophic sources independently of the taxonomy. Shallow tropical sponges and cnidarians from environments showed plant and zooxanthellae sterols in their tissues, while their deep-sea counterparts showed phytoplankton and zooplankton sterols. In contrast, echinoids, a class of echinoderms, the most complex phylum along with hemichordates and chordates (deuterostomes), did not show significant differences in their sterol profile, suggesting that cholesterol synthesis is present in deuterostomes other than chordates.
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Affiliation(s)
- Laura Carreón-Palau
- Department of Ocean Sciences, Memorial University of Newfoundland, Marine Lab Rd., St. John’s, NL A1C 5S7, Canada; (N.Ş.Ö.); (C.C.P.); (C.P.)
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), El Comitán, La Paz, Baja California Sur 23205, Mexico
- Correspondence:
| | - Nurgül Şen Özdemir
- Department of Ocean Sciences, Memorial University of Newfoundland, Marine Lab Rd., St. John’s, NL A1C 5S7, Canada; (N.Ş.Ö.); (C.C.P.); (C.P.)
- Department of Veterinary Medicine, Vocational School of Food, Agriculture and Livestock, Bingöl University, Bingöl 12000, Turkey
| | - Christopher C. Parrish
- Department of Ocean Sciences, Memorial University of Newfoundland, Marine Lab Rd., St. John’s, NL A1C 5S7, Canada; (N.Ş.Ö.); (C.C.P.); (C.P.)
| | - Camilla Parzanini
- Department of Ocean Sciences, Memorial University of Newfoundland, Marine Lab Rd., St. John’s, NL A1C 5S7, Canada; (N.Ş.Ö.); (C.C.P.); (C.P.)
- Department of Chemistry and Biolog, Ryerson University, Toronto, ON M5B 2K3, Canada
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Seel W, Baust D, Sons D, Albers M, Etzbach L, Fuss J, Lipski A. Carotenoids are used as regulators for membrane fluidity by Staphylococcus xylosus. Sci Rep 2020; 10:330. [PMID: 31941915 PMCID: PMC6962212 DOI: 10.1038/s41598-019-57006-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 12/19/2019] [Indexed: 01/10/2023] Open
Abstract
Carotenoids are associated with several important biological functions as antenna pigments in photosynthesis or protectives against oxidative stress. Occasionally they were also discussed as part of the cold adaptation mechanism of bacteria. For two Staphylococcus xylosus strains we demonstrated an increased content of staphyloxanthin and other carotenoids after growth at 10 °C but no detectable carotenoids after grow at 30 °C. By in vivo measurements of generalized polarization and anisotropy with two different probes Laurdan and TMA-DPH we detected a strong increase in membrane order with a simultaneous increase in membrane fluidity at low temperatures accompanied by a broadening of the phase transition. Increased carotenoid concentration was also correlated with an increased resistance of the cells against freeze-thaw stress. In addition, the fatty acid profile showed a moderate adaptation to low temperature by increasing the portion of anteiso-branched fatty acids. The suppression of carotenoid synthesis abolished the effects observed and thus confirmed the causative function of the carotenoids in the modulation of membrane parameters. A differential transcriptome analysis demonstrated the upregulation of genes involved in carotenoid syntheses under low temperature growth conditions. The presented data suggests that upregulated synthesis of carotenoids is a constitutive component in the cold adaptation strategy of Staphylococcus xylosus and combined with modifications of the fatty acid profile constitute the adaptation to grow under low temperature conditions.
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Affiliation(s)
- Waldemar Seel
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Food Microbiology and Hygiene, 53115, Bonn, Germany
| | - Denise Baust
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Food Microbiology and Hygiene, 53115, Bonn, Germany
| | - Dominik Sons
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Food Microbiology and Hygiene, 53115, Bonn, Germany
| | - Maren Albers
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Food Microbiology and Hygiene, 53115, Bonn, Germany
| | - Lara Etzbach
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Molecular Food Technology, 53115, Bonn, Germany
| | - Janina Fuss
- Max Planck-Genome-Centre Cologne, 50829, Cologne, Germany
- Institute of Clinical Molecular Biology, Kiel University (CAU)/University Hospital Schleswig Holstein, 24105, Kiel, Germany
| | - André Lipski
- Rheinische Friedrich-Wilhelms-Universität Bonn, Institute of Nutritional and Food Science, Food Microbiology and Hygiene, 53115, Bonn, Germany.
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6
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Identification of Key Amino Acid Residues Determining Product Specificity of 2,3-Oxidosqualene Cyclase in Siraitia grosvenorii. Catalysts 2018. [DOI: 10.3390/catal8120577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sterols and triterpenes are structurally diverse bioactive molecules generated through cyclization of linear 2,3-oxidosqualene. Based on carbocationic intermediates generated during the initial substrate preorganization step, oxidosqualene cyclases (OSCs) are roughly segregated into a dammarenyl cation group that predominantly catalyzes triterpenoid precursor products and a protosteryl cation group which mostly generates sterol precursor products. The mechanism of conversion between two scaffolds is not well understood. Previously, we have characterized a promiscuous OSC from Siraitia grosvenorii (SgCS) that synthesizes a novel cucurbitane-type triterpene cucurbitadienol as its main product. By integration of homology modeling, molecular docking and site-directed mutagenesis, we discover that five key amino acid residues (Asp486, Cys487, Cys565, Tyr535, and His260) may be responsible for interconversions between chair–boat–chair and chair–chair–chair conformations. The discovery of euphol, dihydrolanosterol, dihydroxyeuphol and tirucallenol unlocks a new path to triterpene diversity in nature. Our findings also reveal mechanistic insights into the cyclization of oxidosqualene into cucurbitane-type and lanostane-type skeletons, and provide a new strategy to identify key residues determining OSC specificity.
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Bennett H, Bell JJ, Davy SK, Webster NS, Francis DS. Elucidating the sponge stress response; lipids and fatty acids can facilitate survival under future climate scenarios. GLOBAL CHANGE BIOLOGY 2018; 24:3130-3144. [PMID: 29505691 DOI: 10.1111/gcb.14116] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/10/2018] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
Ocean warming (OW) and ocean acidification (OA) are threatening coral reef ecosystems, with a bleak future forecast for reef-building corals, which are already experiencing global declines in abundance. In contrast, many coral reef sponge species are able to tolerate climate change conditions projected for 2100. To increase our understanding of the mechanisms underpinning this tolerance, we explored the lipid and fatty acid (FA) composition of four sponge species with differing sensitivities to climate change, experimentally exposed to OW and OA levels predicted for 2100, under two CO2 Representative Concentration Pathways. Sponges with greater concentrations of storage lipid, phospholipids, sterols and elevated concentrations of n-3 and n-6 long-chain polyunsaturated FA (LC PUFA), were more resistant to OW. Such biochemical constituents likely contribute to the ability of these sponges to maintain membrane function and cell homeostasis in the face of environmental change. Our results suggest that n-3 and n-6 LC PUFA are important components of the sponge stress response potentially via chain elongation and the eicosanoid stress-signalling pathways. The capacity for sponges to compositionally alter their membrane lipids in response to stress was also explored using a number of specific homeoviscous adaptation (HVA) indicators. This revealed a potential mechanism via which additional CO2 could facilitate the resistance of phototrophic sponges to thermal stress through an increased synthesis of membrane-stabilizing sterols. Finally, OW induced an increase in FA unsaturation in phototrophic sponges but a decrease in heterotrophic species, providing support for a difference in the thermal response pathway between the sponge host and the associated photosymbionts. Here we have shown that sponge lipids and FA are likely to be an important component of the sponge stress response and may play a role in facilitating sponge survival under future climate conditions.
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Affiliation(s)
- Holly Bennett
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - James J Bell
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Nicole S Webster
- Australian Institute of Marine Science, Townsville, Queensland, Australia
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland, Australia
| | - David S Francis
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
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Plotkin BJ, Konakieva MI. Attenuation of antimicrobial activity by the human steroid hormones. Steroids 2017; 128:120-127. [PMID: 28951169 DOI: 10.1016/j.steroids.2017.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/28/2017] [Accepted: 09/20/2017] [Indexed: 11/16/2022]
Abstract
Upon entering the human host, Staphylococcus aureus is exposed to endogenous steroid hormones. The interaction between S. aureus and dehydroepiandosterone (DHEA) results in an increased resistance to the host cationic defense peptide, β-1 defensin, as well as vancomycin and other antibiotics that have a positive charge. The increased resistance to vancomycin is phenotypic and appears to correlate with a DHEA-mediated alteration in cell surface architecture. DHEA-mediated cell surface changes include alterations in: cell surface charge, surface hydrophobicity, capsule production, and carotenoid production. In addition, exposure to DHEA results in decreased resistance to lysis by Triton X-100 and lysozyme, indicating activation of murien hydrolase activity. We propose that DHEA is an interspecies quorum-like signal that triggers innate phenotypic host survival strategies in S. aureus that include increased carotenoid production and increased vancomycin resistance. Furthermore, this DHEA-mediated survival system may share the cholesterol-squalene pathway shown to be statin sensitive thus, providing a potential pathway for drug targeting.
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Affiliation(s)
- Balbina J Plotkin
- Department of Microbiology and Immunology, Midwestern University, Downers Grove, IL 60515, United States.
| | - Monika I Konakieva
- Department of Chemistry, American University, Washington, DC 20016, United States.
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Di Cola E, Torbensen K, Clemente I, Rossi F, Ristori S, Abou-Hassan A. Lipid-Stabilized Water-Oil Interfaces Studied by Microfocusing Small-Angle X-ray Scattering. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:9100-9105. [PMID: 28816051 DOI: 10.1021/acs.langmuir.7b02076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Water-in-oil (w/o) simple emulsions are dispersed microconfined systems that find applications in many areas of advanced materials and biotechnology, such as the food industry, drug delivery, and cosmetics, to name but a few. In these systems, the structural and chemical properties of the boundary layer at the w/o interface are of paramount importance in determining functionality and stability. Recently, microfluidic methods have emerged as a valuable tool for fabricating monodisperse emulsion droplets. Because of the intrinsic flexibility of microfluidics, different interfaces can be obtained, and general principles governing their stability are needed to guide the experimental approach. Herein, we investigate the structural characteristics of the region encompassing the liquid/liquid (L/L) interface of w/o emulsions generated by a microfluidic device in the presence of phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and other intercalating amphiphiles (dopants) using microfocused small-angle X-rays scattering (μ-SAXS). We show that phospholipids provide a stable and versatile boundary film of ∼100 μm whose basic units are swollen and uncorrelated DMPC bilayers. The internal arrangement of this interfacial film can be tuned by adding molecules with a different packing parameter, such as cholesterol, which is able to increase the stiffness of the lipid membranes and trigger interbilayer correlation.
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Affiliation(s)
- Emanuela Di Cola
- Laboratoire Interdisciplinaire de Physique, Université Grenoble-Alpes , 38402 Saint-Martin-d'Hères, France
| | - Kristian Torbensen
- Sorbonne Universités, UPMC Univ Paris 06 , UMR 8234, Laboratoire Physico-chimie des Electrolytes, Nanosystèmes InterfaciauX (PHENIX), 75252 Paris cedex 05, France
| | - Ilaria Clemente
- Department of Chemistry and Biology, University of Salerno , Fisciano, SA, Italy
| | - Federico Rossi
- Department of Chemistry & CSGI, University of Florence , 50019 Sesto Fiorentino, Italy
| | - Sandra Ristori
- Department of Chemistry and Biology, University of Salerno , Fisciano, SA, Italy
| | - Ali Abou-Hassan
- Sorbonne Universités, UPMC Univ Paris 06 , UMR 8234, Laboratoire Physico-chimie des Electrolytes, Nanosystèmes InterfaciauX (PHENIX), 75252 Paris cedex 05, France
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Yuldasheva NK, Pardaev G, Ul’chenko NT, Normakhmatov R, Glushenkova AI. Lipids from Kernels of Several Stone Fruits. Chem Nat Compd 2017. [DOI: 10.1007/s10600-017-2101-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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12
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Zhao Y, Li J. Ascidian bioresources: common and variant chemical compositions and exploitation strategy - examples of Halocynthia roretzi, Styela plicata, Ascidia sp. and Ciona intestinalis. ACTA ACUST UNITED AC 2016; 71:165-80. [PMID: 27049617 DOI: 10.1515/znc-2016-0012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/06/2016] [Indexed: 12/17/2022]
Abstract
To explore abundant marine ascidian bioresources, four species from two orders have been compared in their chemical compositions. After a universal separation of the animal body into two fractions, all tunics have been found rich in carbohydrate contents, while all inner body tissues are richer in proteins. Cellulose is present almost exclusively in the tunics and more in the order Stolidobranchia, while more sulfated polysaccharides are present in Phlebobranchia species. Almost all proteins are collagens with a high essential amino acid index and high delicious amino acid (DAA) content. All fractions also have high contents of good-quality fatty acids and trace minerals but low toxic element contents, with different sterols and glycosaminoglycans. There are species-specific characteristics observed for vanadium accumulation and sterol structures which are also meaningful for ascidian chemotaxonomy and resource exploitation. It is suggested that in addition to the present utilizations of tunics for cellulose production and of some species' inner body tissues as human food, one should explore all species' inner body tissues as human foods and all tunics as food or animal feed with the contained cellulose as dietary fiber. Collagens, sulfated polysaccharides, glycosaminoglycans, sterols and trace elements could be explored as byproducts for, e.g. pharmaceutical and chemical industries.
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13
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From hopanoids to cholesterol: Molecular clocks of pentameric ligand-gated ion channels. Prog Lipid Res 2016; 63:1-13. [DOI: 10.1016/j.plipres.2016.03.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 11/21/2022]
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Hargrove TY, Friggeri L, Wawrzak Z, Sivakumaran S, Yazlovitskaya EM, Hiebert SW, Guengerich FP, Waterman MR, Lepesheva GI. Human sterol 14α-demethylase as a target for anticancer chemotherapy: towards structure-aided drug design. J Lipid Res 2016; 57:1552-63. [PMID: 27313059 DOI: 10.1194/jlr.m069229] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/20/2022] Open
Abstract
Rapidly multiplying cancer cells synthesize greater amounts of cholesterol to build their membranes. Cholesterol-lowering drugs (statins) are currently in clinical trials for anticancer chemotherapy. However, given at higher doses, statins cause serious side effects by inhibiting the formation of other biologically important molecules derived from mevalonate. Sterol 14α-demethylase (CYP51), which acts 10 steps downstream, is potentially a more specific drug target because this portion of the pathway is fully committed to cholesterol production. However, screening a variety of commercial and experimental inhibitors of microbial CYP51 orthologs revealed that most of them (including all clinical antifungals) weakly inhibit human CYP51 activity, even if they display high apparent spectral binding affinity. Only one relatively potent compound, (R)-N-(1-(3,4'-difluorobiphenyl-4-yl)-2-(1H-imidazol-1-yl)ethyl)-4-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamide (VFV), was identified. VFV has been further tested in cellular experiments and found to decrease proliferation of different cancer cell types. The crystal structures of human CYP51-VFV complexes (2.0 and 2.5 Å) both display a 2:1 inhibitor/enzyme stoichiometry, provide molecular insights regarding a broader substrate profile, faster catalysis, and weaker susceptibility of human CYP51 to inhibition, and outline directions for the development of more potent inhibitors.
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Affiliation(s)
- Tatiana Y Hargrove
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Laura Friggeri
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Science Collaborative Access Team, Northwestern University, Argonne, IL
| | - Suneethi Sivakumaran
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Michael R Waterman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Galina I Lepesheva
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232
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Stimulation of Na(+),K(+)-ATPase Activity as a Possible Driving Force in Cholesterol Evolution. J Membr Biol 2015; 249:251-9. [PMID: 26715509 DOI: 10.1007/s00232-015-9864-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/09/2015] [Indexed: 12/19/2022]
Abstract
Cholesterol is exclusively produced by animals and is present in the plasma membrane of all animal cells. In contrast, the membranes of fungi and plants contain other sterols. To explain the exclusive preference of animal cells for cholesterol, we propose that cholesterol may have evolved to optimize the activity of a crucial protein found in the plasma membrane of all multicellular animals, namely the Na(+),K(+)-ATPase. To test this hypothesis, mirror tree and phylogenetic distribution analyses have been conducted of the Na(+),K(+)-ATPase and 3β-hydroxysterol Δ(24)-reductase (DHCR24), the last enzyme in the Bloch cholesterol biosynthetic pathway. The results obtained support the hypothesis of a co-evolution of the Na(+),K(+)-ATPase and DHCR24. The evolutionary correlation between DHCR24 and the Na(+),K(+)-ATPase was found to be stronger than between DHCR24 and any other membrane protein investigated. The results obtained, thus, also support the hypothesis that cholesterol evolved together with the Na(+),K(+)-ATPase in multicellular animals to support Na(+),K(+)-ATPase activity.
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Mpofu LT, McLaren NW. Ergosterol concentration and variability in genotype-by-pathogen interaction for grain mold resistance in sorghum. PLANTA 2014; 240:239-250. [PMID: 24817586 PMCID: PMC4107276 DOI: 10.1007/s00425-014-2081-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/18/2014] [Indexed: 06/03/2023]
Abstract
A lack of understanding of host-by-pathogen relations can hinder the success of breeding for resistance to a major disease. Fungal strain pathogenicity has to be understood from the virulence it can cause on susceptible genotypes and host resistance indicates which genotypes have resistance genes. Where the two worlds meet lies the place where researchers match the prevalent pathogen in the area of production with resistant varieties. This paper uses ergosterol concentration analysis as a measure of fungal biomass accumulation to assess levels of resistance in host genotypes. 11 sorghum genotypes were inoculated with 5 strains of fungi that are known to be associated with grain mold disease of sorghum. The resulting interaction was analyzed using GGE Biplot analysis and Cluster analysis which showed that none of the genotypes were resistant to Phoma sorghina and Curvularia lunata. Three genotypes were resistant to Fusarium thapsinum. One fungal strain (Alternaria alternata) does not contribute any significant damage in the grain mold disease. Fusarium graminearum causes very little grain mold disease. There was no correlation between the fungal strains. Visual scoring did not correlate with ergosterol accumulation. Resistance to grain mold in sorghum is shown to be due to vertical or specific resistance genes. Sorghum breeders should, therefore, identify predominant fungal strains in their localities and then locate and tag these resistance genes in their germplasm and pyramid them in commercial varieties.
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Lönnfors M, Engberg O, Peterson BR, Slotte JP. Interaction of 3β-amino-5-cholestene with phospholipids in binary and ternary bilayer membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:648-55. [PMID: 22128897 PMCID: PMC3265605 DOI: 10.1021/la203589u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
3β-Amino-5-cholestene (aminocholesterol) is a synthetic sterol whose properties in bilayer membranes have been examined. In fluid palmitoyl sphingomyelin (PSM) bilayers, aminocholesterol and cholesterol were equally effective in increasing acyl chain order, based on changes in diphenylhexatriene (DPH) anisotropy. In fluid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers, aminocholesterol ordered acyl chains, but slightly less efficiently than cholesterol. Aminocholesterol eliminated the PSM and DPPC gel-to-liquid crystalline phase transition enthalpy linearly with concentration, and the enthalpy approached zero at 30 mol % sterol. Whereas cholesterol was able to increase the thermostability of ordered PSM domains in a fluid bilayer, aminocholesterol under equal conditions failed to do this, suggesting that its interaction with PSM was not as favorable as cholesterols. In ternary mixed bilayers, containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), PSM or DPPC, and cholesterol at proportions to contain a liquid-ordered phase (60:40 by mol of POPC and PSM or DPPC, and 30 mol % cholesterol), the average lifetime of trans-parinaric acid (tPA) was close to 20 ns. When cholesterol was replaced with aminocholesterol in such mixed bilayers, the average lifetime of tPA was only marginally shorter (about 18 ns). This observation, together with acyl chain ordering data, clearly shows that aminocholesterol was able to form a liquid-ordered phase with saturated PSM or DPPC. We conclude that aminocholesterol should be a good sterol replacement in model membrane systems for which a partial positive charge is deemed beneficial.
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Affiliation(s)
- Max Lönnfors
- Biochemistry, Department of Biosciences, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Oskar Engberg
- Biochemistry, Department of Biosciences, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Blake R. Peterson
- Department of Medicinal Chemistry, the University of Kansas, 2034 Becker Dr., Lawrence, KS, 66047, USA
| | - J. Peter Slotte
- Biochemistry, Department of Biosciences, Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
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Lepesheva GI, Villalta F, Waterman MR. Targeting Trypanosoma cruzi sterol 14α-demethylase (CYP51). ADVANCES IN PARASITOLOGY 2011; 75:65-87. [PMID: 21820552 DOI: 10.1016/b978-0-12-385863-4.00004-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
There are at least two obvious features that must be considered upon targeting specific metabolic pathways/enzymes for drug development: the pathway must be essential and the enzyme must allow the design of pharmacologically useful inhibitors. Here, we describe Trypanosoma cruzi sterol 14α-demethylase as a promising target for anti-Chagasic chemotherapy. The use of anti-fungal azoles, which block sterol biosynthesis and therefore membrane formation in fungi, against the protozoan parasite has turned out to be highly successful: a broad spectrum anti-fungal drug, the triazole compound posaconazole, is now entering phase II clinical trials for treatment of Chagas disease. This review summarizes comparative information on anti-fungal azoles and novel inhibitory scaffolds selective for Trypanosomatidae sterol 14α-demethylase through the lens of recent structure/functional characterization of the target enzyme. We believe our studies open wide opportunities for rational design of novel, pathogen-specific and therefore more potent and efficient anti-trypanosomal drugs.
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Affiliation(s)
- Galina I Lepesheva
- Department of Biochemistry School of Medicine, Vanderbilt University, Nashville, Tennessee, USA
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Stevens MM, Honerkamp-Smith AR, Keller SL. Solubility Limits of Cholesterol, Lanosterol, Ergosterol, Stigmasterol, and β-Sitosterol in Electroformed Lipid Vesicles. SOFT MATTER 2010; 6:5882-5890. [PMID: 21731574 PMCID: PMC3124637 DOI: 10.1039/c0sm00373e] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Here we use nuclear magnetic resonance to measure the solubility limit of several biologically relevant sterols in electroformed giant unilamellar vesicle membranes containing phosphatidylcholine (PC) lipids in ratios of 1:1:X DOPC:DPPC:sterol. We find solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and β-sitosterol to be 65-70%, ~35%, 30-35%, 20-25%, and ~40%, respectively. The low solubilities of stigmasterol and β-sitosterol, which differ from cholesterol only in their alkyl tails, show that subtle differences in tail structure can strongly affect sterol solubility. Below the solubility limits, the fraction of sterol to PC-lipid in electroformed vesicles linearly reflects the fraction in the original stock solutions used in the electroformation process.
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Affiliation(s)
- Mark M Stevens
- Dept. of Chemistry 351700, University of Washington, Seattle, WA 98195-1700
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20
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Baird TD, DeLorenzo ME. Descriptive and mechanistic toxicity of conazole fungicides using the model test alga Dunaliella tertiolecta (Chlorophyceae). ENVIRONMENTAL TOXICOLOGY 2010; 25:213-220. [PMID: 19382186 DOI: 10.1002/tox.20493] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Conazole fungicides are commonly used to prevent fungal growth on turf grass and agricultural crops. As many of these sites are adjacent to coastal waterways and estuaries, there exists the potential for nontarget effects of runoff on marine organisms. This study reports 96 h EC(50) values for four selected conazole fungicides (triadimefon = 5.98 mg/L; triadimenol = 5.51 mg/L; propiconazole = 2.33 mg/L; hexaconazole = 0.91 mg/L) to the model test alga Dunaliella tertiolecta. We further investigated possible mechanisms of toxicity by examining sublethal effects of exposure on cell morphology, osmoregulatory function, and lipid composition. These mechanistic studies revealed that conazole exposure does not inhibit synthesis of the cell's glycerol osmolyte, but does result in an overall increase in cellular volume and total lipid content. Both fungi and chlorophytes rely on ergosterol to maintain membrane structure and fluidity, and we provide evidence that the sterol-inhibiting conazoles may interfere with ergosterol biosynthesis in the cell membrane of Dunaliella. These findings suggest that green algae may be especially susceptible to nontarget effects of sterol-inhibiting fungicides in marine systems.
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Affiliation(s)
- Thomas D Baird
- Grice Marine Biological Laboratory, College of Charleston, 205 Fort Johnson Rd., Charleston, SC 29412, USA
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22
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Ul’chenko NT, Bekker NP, Yunusov O, Yuldasheva NK, Chernenko TV, Glushenkova AI. Lipids and lipophilic components from seeds of some fruit plants. Chem Nat Compd 2009. [DOI: 10.1007/s10600-009-9353-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Frickey T, Kannenberg E. Phylogenetic analysis of the triterpene cyclase protein family in prokaryotes and eukaryotes suggests bidirectional lateral gene transfer. Environ Microbiol 2009; 11:1224-41. [PMID: 19207562 DOI: 10.1111/j.1462-2920.2008.01851.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Functional constraints to modifications in triterpene cyclase amino acid sequences make them good candidates for evolutionary studies on the phylogenetic relatedness of these enzymes in prokaryotes as well as in eukaryotes. In this study, we used a set of identified triterpene cyclases, a group of mainly bacterial squalene cyclases and a group of predominantly eukaryotic oxidosqualene cyclases, as seed sequences to identify 5288 putative triterpene cyclase homologues in publicly available databases. The Cluster Analysis of Sequences software was used to detect groups of sequences with increased pairwise sequence similarity. The sequences fall into two main clusters, a bacterial and a eukaryotic. The conserved, informative regions of a multiple sequence alignment of the family were used to construct a neighbour-joining phylogenetic tree using the AsaturA and maximum likelihood phylogenetic tree using the PhyML software. Both analyses showed that most of the triterpene cyclase sequences were similarly grouped to the accepted taxonomic relationships of the organism the sequences originated from, supporting the idea of vertical transfer of cyclase genes from parent to offspring as the main evolutionary driving force in this protein family. However, a small group of sequences from three bacterial species (Stigmatella, Gemmata and Methylococcus) grouped with an otherwise purely eukaryotic cluster of oxidosqualene cyclases, while a small group of sequences from seven fungal species and a sequence from the fern Adiantum grouped consistently with a cluster of otherwise purely bacterial squalene cyclases. This suggests that lateral gene transfer may have taken place, entailing a transfer of oxidosqualene cyclases from eukaryotes to bacteria and a transfer of squalene cyclase from bacteria to an ancestor of the group of Pezizomycotina fungi.
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Affiliation(s)
- Tancred Frickey
- Max Planck Institut fuer Entwicklungsbiologie, Tübingen, Germany
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24
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Yoss NL, Mahfouz MM, Diao HS, Kummerow FA. Sphingomyelin Favors. Precipitation of Negatively Charged Liposomes in 1 mM Ca2+. J Liposome Res 2008. [DOI: 10.3109/08982109209018638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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25
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CYP51: A major drug target in the cytochrome P450 superfamily. Lipids 2008; 43:1117-25. [PMID: 18769951 DOI: 10.1007/s11745-008-3225-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 08/08/2008] [Indexed: 10/21/2022]
Abstract
The cytochrome P540 (CYP) superfamily currently includes about 9000 proteins forming more than 800 families. The enzymes catalyze monooxygenation of a vast array of compounds and play essentially two roles. They provide biodefense (detoxification of xenobiotics, antibiotic production) and participate in biosynthesis of important endogenous molecules, particularly steroids. Based on these two roles, sterol 14/*alpha*/-demethylases (CYP51) belong to the second group of P450s. The CYP51 family, however, is very special as its members preserve strict functional conservation in enzyme activity in all biological kingdoms. At amino acid identity across the kingdoms as low as 25-30%, they all catalyze essentially the same three-step reaction of oxidative removal of the 14/*alpha*/-methyl group from the lanostane frame. This reaction is the required step in sterol biosynthesis of pathogenic microbes. We have shown that specific inhibition of protozoan CYP51 can potentially provide treatment for human trypanosomiases. Three sets of CYP51 inhibitors tested in vitro and in trypanosomal cells in this study include azoles [best results being 50% cell growth inhibition at <1 and at 1.3 muM for Trypanosoma cruzi (TC) and Trypanosoma brucei (TB), respectively], non-azole compounds (50% TC cell growth inhibition at 5 microM) and substrate analogs of the 14/*alpha*/-demethylase reaction. 32-Methylene cyclopropyl lanost-7-enol exhibited selectivity toward TC with 50% cell growth inhibition at 3 microM.
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Interfacial behavior of cholesterol, ergosterol, and lanosterol in mixtures with DPPC and DMPC. Biophys J 2008; 95:2340-55. [PMID: 18515391 DOI: 10.1529/biophysj.108.132076] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Binary mixtures of cholesterol, ergosterol, and lanosterol with phosphatidylcholines differing in the length of the saturated acyl chains, viz 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-myristoyl-sn-glycero-3-phosphocholine (DMPC), were analyzed using a Langmuir balance for recording force-area (pi-A) and surface potential-area (psi-A) isotherms. A progressive disappearance of the liquid expanded-liquid condensed transition was observed in mixed monolayers with DPPC after the increase in the content of all three sterols. For fluid DMPC matrix, no modulation of the monolayer phase behavior due to the sterols was evident with the exception of lanosterol, for which a pronounced discontinuity between mole fractions of X = 0.3 and X = 0.75 was discernible in the compression isotherms. Condensing and expanding effects in force-area (pi-A) isotherms due to varying X(sterols) and differences in the monolayer physical state were assessed from the values for the interfacial compression moduli. Surface potential measurements support the notion that cholesterol and ergosterol, but not lanosterol, reduce the penetration of water into the lipid monolayers. Examination of the excess free energy of mixing revealed an enhanced stability of binary monolayers containing cholesterol compared to those with ergosterol or lanosterol; the differences are emphasized in the range of surface pressure values found in natural membranes.
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Wu TK, Chang CH, Liu YT, Wang TT. Saccharomyces cerevisiaeoxidosqualene-lanosterol cyclase: A chemistry-biology interdisciplinary study of the protein's structure-function-reaction mechanism relationships. CHEM REC 2008; 8:302-25. [DOI: 10.1002/tcr.20157] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
Sterols such as cholesterol are important components of cellular membranes. They are not uniformly distributed among organelles and maintaining the proper distribution of sterols is critical for many cellular functions. Both vesicular and non-vesicular pathways move sterols between membranes and into and out of cells. There is growing evidence that a number of non-vesicular transport pathways operate in cells and, in the past few years, a number of proteins have been proposed to facilitate this transfer. Some are soluble sterol transfer proteins that may move sterol between membranes. Others are integral membranes proteins that mediate sterol efflux, uptake from cells, and perhaps intracellular sterol transfer as well. In most cases, the mechanisms and regulation of these proteins remains poorly understood. This review summarizes our current knowledge of these proteins and how they could contribute to intracellular sterol trafficking and distribution.
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Affiliation(s)
- William A Prinz
- Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, US Department of Health and Human Services, Bethesda, MD 20892, USA.
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29
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Bragina NA, Chupin VV. Methods of synthesis of deuterium-labelled lipids. RUSSIAN CHEMICAL REVIEWS 2007. [DOI: 10.1070/rc1997v066n11abeh000369] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Mans C, Brown CJ. Radiographic Evidence of Atherosclerosis of the Descending Aorta in a Grey-cheeked Parakeet (Brotogeris pyrrhopterus). J Avian Med Surg 2007; 21:56-62. [DOI: 10.1647/1082-6742(2007)21[56:reoaot]2.0.co;2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Souchet N, Laplante S. Seasonal and geographical variations of sterol composition in snow crab hepatopancreas and pelagic fish viscera from Eastern Quebec. Comp Biochem Physiol B Biochem Mol Biol 2007; 147:378-86. [PMID: 17374564 DOI: 10.1016/j.cbpb.2007.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 02/02/2007] [Accepted: 02/05/2007] [Indexed: 11/30/2022]
Abstract
Sterol composition was determined in snow crab hepatopancreas and mackerel and herring viscera for various locations and collection periods. A simple and valuable method, using direct saponification and extraction with water-cyclohexane has been optimized to recover total sterol. They were identified and quantified as trimethylsilyl ether derivatives by GC-MS analysis. Method validation indicated excellent sensitivity (limit of quantification: 1.25 mg/100 g wet basis for cholesterol and desmosterol; 0.03-0.05 mg/100 g for other sterols), good reproducibility (CV%: 1.5-6.8) and accuracy (recovery%: 94-107). In crab hepatopancreas, cholesterol was the main sterol (67-76%), followed by desmosterol (19-24%). Phytosterols and molluscan sterols were also present in low quantity. A lower total sterol content with different composition was found in crabs from Magdalen Islands compared to those from Gaspé Peninsula or North Shore of the St-Lawrence Gulf. No seasonal variation was observed between collection periods, which were probably too close. Mackerel and herring viscera contained the same sterols as crab except for campesterol and sitosterol, but the cholesterol proportion was higher (93-98%). The higher abundance of sterols in herring caught in September vs. May would be related to an increase of the body lipid content during the summer.
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Affiliation(s)
- Nathalie Souchet
- Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, Rimouski, Québec, Canada
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32
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Néchet SL, Dubois N, Gouygou JP, Bergé JP. Lipid composition of the liver oil of the ray, Himantura bleekeri. Food Chem 2007. [DOI: 10.1016/j.foodchem.2006.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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33
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Lösel DM. Synthesis and functioning of membrane lipids in fungi and infected plants. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780320309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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34
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Buchenauer H. Inhibition of ergosterol biosynthesis by triadimenol inUstilago avenae. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780090603] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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35
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Bossche HV, Lauwers W, Willemsens G, Marichal P, Cornelissen F, Cools W. Molecular basis for the antimycotic and antibacterial activity ofN-substituted imidazoles and triazoles: The inhibition of isoprenoid biosynthesis. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780150210] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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36
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Stottrup BL, Keller SL. Phase behavior of lipid monolayers containing DPPC and cholesterol analogs. Biophys J 2006; 90:3176-83. [PMID: 16461392 PMCID: PMC1432104 DOI: 10.1529/biophysj.105.072959] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigate the miscibility phase behavior of lipid monolayers containing a wide variety of sterols. Six of the sterols satisfy a definition from an earlier study of "membrane-active sterols" in bilayers (cholesterol, epicholesterol, lathosterol, dihydrocholesterol, ergosterol, and desmosterol), and six do not (25-hydroxycholesterol, lanosterol, androstenolone, coprostanol, cholestane, and cholestenone). We find that monolayers containing dipalmitoyl phosphatidylcholine mixed with membrane-active sterols generally produce phase diagrams containing two distinct regions of immiscible liquid phases, whereas those with membrane-inactive sterols generally do not. This observation establishes a correlation between lipid monolayers and bilayers. It also demonstrates that the ability to form two regions of immiscibility in monolayers is not one of the biophysical attributes that explains cholesterol's predominance in animal cell membranes. Furthermore, we find unusual phase behavior for dipalmitoyl phosphatidylcholine monolayers containing 25-hydroxycholesterol, which produce both an upper and a lower miscibility transition. The lower transition correlates with a sharp change of slope in the pressure-area isotherm.
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Affiliation(s)
- Benjamin L Stottrup
- Departments of Physics and Chemistry, University of Washington, Seattle, Washington 98195, USA
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Engineering Pathway Enzymes to Understand the Function and Evolution of Sterol Structure and Activity. RECENT ADVANCES IN PHYTOCHEMISTRY 2006. [DOI: 10.1016/s0079-9920(06)80043-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Henriksen J, Rowat AC, Brief E, Hsueh YW, Thewalt JL, Zuckermann MJ, Ipsen JH. Universal behavior of membranes with sterols. Biophys J 2005; 90:1639-49. [PMID: 16326903 PMCID: PMC1367315 DOI: 10.1529/biophysj.105.067652] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Lanosterol is the biosynthetic precursor of cholesterol and ergosterol, sterols that predominate in the membranes of mammals and lower eukaryotes, respectively. These three sterols are structurally quite similar, yet their relative effects on membranes have been shown to differ. Here we study the effects of cholesterol, lanosterol, and ergosterol on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipid bilayers at room temperature. Micropipette aspiration is used to determine membrane material properties (area compressibility modulus), and information about lipid chain order (first moments) is obtained from deuterium nuclear magnetic resonance. We compare these results, along with data for membrane-bending rigidity, to explore the relationship between membrane hydrophobic thickness and elastic properties. Together, such diverse approaches demonstrate that membrane properties are affected to different degrees by these structurally distinct sterols, yet nonetheless exhibit universal behavior.
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Affiliation(s)
- J Henriksen
- MEMPHYS - Centre for Biomembrane Physics, Department of Physics, Syddansk Universitet, Odense, Denmark
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Pencer J, Nieh MP, Harroun TA, Krueger S, Adams C, Katsaras J. Bilayer thickness and thermal response of dimyristoylphosphatidylcholine unilamellar vesicles containing cholesterol, ergosterol and lanosterol: A small-angle neutron scattering study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1720:84-91. [PMID: 16386704 DOI: 10.1016/j.bbamem.2005.10.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 10/19/2005] [Accepted: 10/31/2005] [Indexed: 10/25/2022]
Abstract
Small-angle neutron scattering (SANS) measurements are performed on pure dimyristoyl phosphatidylcholine (DMPC) unilamellar vesicles (ULV) and those containing either 20 or 47 mol% cholesterol, ergosterol or lanosterol. From the SANS data, we were able to determine the influence of these sterols on ULV bilayer thickness and vesicle area expansion coefficients. While these parameters have been determined previously for membranes containing cholesterol, to the best of our knowledge, this is the first time such results have been presented for membranes containing the structurally related sterols, ergosterol and lanosterol. At both molar concentrations and at temperatures ranging from 10 to 45 degrees C, the addition of the different sterols leads to increases in bilayer thickness, relative to pure DMPC. We observe large differences in the influence of these sterols on the membrane thermal area expansion coefficient. All three sterols, however, produce very similar changes to membrane thickness.
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Affiliation(s)
- Jeremy Pencer
- NRC, Canadian Neutron Beam Centre, Chalk River Labs, Chalk River, ON, Canada K0J 1J0.
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Burguière A, Hitchen PG, Dover LG, Dell A, Besra GS. Altered expression profile of mycobacterial surface glycopeptidolipids following treatment with the antifungal azole inhibitors econazole and clotrimazole. MICROBIOLOGY-SGM 2005; 151:2087-2095. [PMID: 15942015 DOI: 10.1099/mic.0.27938-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The azole antifungal drugs econazole and clotrimazole are known cytochrome P450 enzyme inhibitors. This study shows that these drugs are potent inhibitors of mycobacterial growth and are more effective against Mycobacterium smegmatis than isoniazid and ethionamide, two established anti-mycobacterial drugs. Several non-tuberculous mycobacteria, including the pathogenic members of the Mycobacterium avium-intracellulare complex (MAC) and the fast-growing saprophytic organism M. smegmatis, produce an array of serovar-specific (ss) and non-serovar-specific (ns) glycopeptidolipids (GPLs). GPL biosynthesis has been investigated for several years but has still not been fully elucidated. The authors demonstrate here that econazole and clotrimazole inhibit GPL biosynthesis in M. smegmatis. In particular, clotrimazole inhibits all four types of nsGPLs found in M. smegmatis, suggesting an early and common target within their biosynthetic pathway. Altogether, the data suggest that an azole-specific target, most likely a cytochrome P450, may be involved in the hydroxylation of the N-acyl chain in GPL biosynthesis. Azole antifungal drugs and potential derivatives could represent an interesting new range of anti-mycobacterial drugs, especially against opportunistic human pathogens including MAC, M. scrofulaceum, M. peregrinum, M. chelonae and M. abscessus.
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Affiliation(s)
- Adeline Burguière
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Paul G Hitchen
- Department of Biological Sciences, Imperial College, London, SW7 2AZ, UK
| | - Lynn G Dover
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Anne Dell
- Department of Biological Sciences, Imperial College, London, SW7 2AZ, UK
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Kers JA, Cameron KD, Joshi MV, Bukhalid RA, Morello JE, Wach MJ, Gibson DM, Loria R. A large, mobile pathogenicity island confers plant pathogenicity on Streptomyces species. Mol Microbiol 2005; 55:1025-33. [PMID: 15686551 DOI: 10.1111/j.1365-2958.2004.04461.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Potato scab is a globally important disease caused by polyphyletic plant pathogenic Streptomyces species. Streptomyces acidiscabies, Streptomyces scabies and Streptomyces turgidiscabies possess a conserved biosynthetic pathway for the nitrated dipeptide phytotoxin thaxtomin. These pathogens also possess the nec1 gene which encodes a necrogenic protein that is an independent virulence factor. In this article we describe a large (325-660 kb) pathogenicity island (PAI) conserved among these three plant pathogenic Streptomyces species. A partial DNA sequence of this PAI revealed the thaxtomin biosynthetic pathway, nec1, a putative tomatinase gene, and many mobile genetic elements. In addition, the PAI from S. turgidiscabies contains a plant fasciation (fas) operon homologous to and colinear with the fas operon in the plant pathogen Rhodococcus fascians. The PAI was mobilized during mating from S. turgidiscabies to the non-pathogens Streptomyces coelicolor and Streptomyces diastatochromogenes on a 660 kb DNA element and integrated site-specifically into a putative integral membrane lipid kinase. Acquisition of the PAI conferred a pathogenic phenotype on S. diastatochromogenes but not on S. coelicolor. This PAI is the first to be described in a Gram-positive plant pathogenic bacterium and is responsible for the emergence of new plant pathogenic Streptomyces species in agricultural systems.
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Affiliation(s)
- Johan A Kers
- Department of Plant Pathology, Cornell University, Ithaca, NY, USA
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Barenholz Y. Sphingomyelin and cholesterol: from membrane biophysics and rafts to potential medical applications. Subcell Biochem 2004; 37:167-215. [PMID: 15376621 DOI: 10.1007/978-1-4757-5806-1_5] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The preferential sphingomyelin-cholesterol interaction which results from the structure and the molecular properties of these two lipids seems to be the physicochemical basis for the formation and maintenance of cholesterol/sphingolipid-enriched nano- and micro-domains (referred to as membrane "rafts") in the plane of plasma and other organelle (i.e., Golgi) membranes. This claim is supported by much experimental evidence and also by theoretical considerations. However, although there is a large volume of information about these rafts regarding their lipid and protein composition, their size, and their dynamics, there is still much to be clarified on these issues, as well as on how rafts are formed and maintained. It is well accepted now that the lipid phase of the rafts is the liquid ordered (LO) phase. However, other (non-raft) parts of the membrane may also be in the LO phase. There are indications that the raft LO phase domains are more tightly packed than the non-raft LO phase, possibly due to intermolecular hydrogen bonding involving sphingolipid and cholesterol. This also explains why the former are detergent-resistant membranes (DRM), while the non-raft LO phase domains are detergent-soluble (sensitive) membranes (DSM). Recent findings suggest that protein-protein interactions such as cross-linking can be controlled by protein distribution between raft and non-raft domains, and, as well, these interactions affect raft size distribution. The cholesterol/sphingomyelin-enriched rafts seem to be involved in many biological processes, mediated by various receptors, as exemplified by various lipidated glycosylphosphatidylinositol (GPI)- and acyl chain-anchored proteins that reside in the rafts. The rafts serve as signaling platforms in the cell. Various pathogens (viruses and toxins) utilize the raft domains on the host cell membrane as a port of entry, site of assembly (viruses), and port of exit (viral budding). Existence and maintenance of cholesterol-sphingomyelin rafts are dependent on the level of membrane cholesterol and sphingomyelin. This explains why reduction of cholesterol level--either through reverse cholesterol transport, using cholesterol acceptors such as beta-cyclodextrin, or through cholesterol biosynthesis inhibition using statins--interferes with many processes which involve rafts and can be applied to treating raft-related infections and diseases. Detailed elucidation of raft structure and function will improve understanding of biological membrane composition-structure-function relationships and also may serve as a new avenue for the development of novel treatments for major diseases, including viral infections, neurodegenerative diseases (Alzheimer's), atherosclerosis, and tumors.
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Affiliation(s)
- Yechezkel Barenholz
- Laboratory of Membrane and Liposome Research, The Hebrew University--Hadassah Medical School, Jerusalem, Israel
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Jackson CJ, Lamb DC, Marczylo TH, Parker JE, Manning NL, Kelly DE, Kelly SL. Conservation and cloning of CYP51: a sterol 14 alpha-demethylase from Mycobacterium smegmatis. Biochem Biophys Res Commun 2003; 301:558-63. [PMID: 12565899 DOI: 10.1016/s0006-291x(02)03078-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The genetic locus encoding cytochrome P450 51 (CYP51; P450(14DM)) in Mycobacterium smegmatis is described here together with confirmation of activity in lanosterol 14 alpha-demethylation. The protein bound azole antifungals with high affinity and the rank order based on affinity matched the ranked order for microbiological sensitivity of the organism, thus supporting a possible role for CYP51 as a target in the antimycobacterial activity of these compounds. Non-saponifiable lipids were extracted from the bacteria grown on minimal medium. Unlike a previous report using growth on complex medium, no cholesterol was detected in two strains of M. smegmatis, but a novel lipid was detected. The genetic locus of CYP51 is discussed in relation to function; it is conserved as part of a putative operon in M. smegmatis, Mycobacterium tuberculosis, Mycobacterium avium, and Mycobacterium bovis and consists of six open-reading frames including two CYPs and a ferredoxin under a putative Tet-R regulated promoter.
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Affiliation(s)
- Colin J Jackson
- Wolfson Laboratory of P450 Biodiversity, Institute of Biological Sciences, University of Wales, Aberystwyth, Wales, SY23 3DA, UK
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Lamb DC, Fowler K, Kieser T, Manning N, Podust LM, Waterman MR, Kelly DE, Kelly SL. Sterol 14alpha-demethylase activity in Streptomyces coelicolor A3(2) is associated with an unusual member of the CYP51 gene family. Biochem J 2002; 364:555-62. [PMID: 12023899 PMCID: PMC1222601 DOI: 10.1042/bj20011380] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The annotation of the genome sequence of Streptomyces coelicolor A3(2) revealed a cytochrome P450 (CYP) resembling various sterol 14alpha-demethylases (CYP51). The putative CYP open reading frame (SC7E4.20) was cloned with a tetrahistidine tag appended to the C-terminus and expressed in Escherichia coli. Protein purified to electrophoretic homogeneity was observed to bind the 14-methylated sterols lanosterol and 24-methylene-24,25-dihydrolanosterol (24-MDL). Reconstitution experiments with E. coli reductase partners confirmed activity in 14alpha-demethylation for 24-MDL, but not lanosterol. An S. coelicolor A3(2) mutant containing a transposon insertion in the CYP51 gene, which will abolish synthesis of the functional haemoprotein, was isolated as a viable strain, the first time a CYP51 has been identified as non-essential. The role of this CYP in bacteria is intriguing. No sterol product was detected in non-saponifiable cell extracts of the parent S. coelicolor A3(2) strain or of the mutant. S. coelicolor A3(2) CYP51 contains very few of the conserved CYP51 residues and, even though it can catalyse 14alpha-demethylation, it probably has another function in Streptomyces. We propose that it is a member of a new CYP51 subfamily.
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Affiliation(s)
- David C Lamb
- Wolfson Laboratory of P450 Biodiversity, Institute of Biological Sciences, University of Wales Aberystwyth, Aberystwyth SY23 3DA, Wales, UK
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Abstract
Proton and/or sodium electrochemical gradients are critical to energy handling at the plasma membranes of all living cells. Sodium gradients are used for animal plasma membranes, all other living organisms use proton gradients. These chemical and electrical gradients are either created by a cation pumping ATPase or are created by photons or redox, used to make ATP. It has been established that both hydrogen and sodium ions leak through lipid bilayers at approximately the same rate at the concentration they occur in living organisms. Although the gradients are achieved by pumping the cations out of the cell, the plasma membrane potential enhances the leakage rate of these cations into the cell because of the orientation of the potential. This review proposes that cells use certain lipids to inhibit cation leakage through the membrane bilayers. It assumes that Na(+) leaks through the bilayer by a defect mechanism. For Na(+) leakage in animal plasma membranes, the evidence suggests that cholesterol is a key inhibitor of Na(+) leakage. Here I put forth a novel mechanism for proton leakage through lipid bilayers. The mechanism assumes water forms protonated and deprotonated clusters in the lipid bilayer. The model suggests how two features of lipid structures may inhibit H(+) leakage. One feature is the fused ring structure of sterols, hopanoids and tetrahymenol which extrude water and therefore clusters from the bilayer. The second feature is lipid structures that crowd the center of the bilayer with hydrocarbon. This can be accomplished either by separating the two monolayers with hydrocarbons such as isoprenes or isopranes in the bilayer's cleavage plane or by branching the lipid chains in the center of the bilayers with hydrocarbon. The natural distribution of lipids that contain these features are examined. Data in the literature shows that plasma membranes exposed to extreme concentrations of cations are particularly rich in the lipids containing the predicted qualities. Prokaryote plasma membranes that reside in extreme acids (acidophiles) contain both hopanoids and iso/anteiso- terminal lipid branching. Plasma membranes that reside in extreme base (alkaliphiles) contain both squalene and iso/anteiso- lipids. The mole fraction of squalene in alkaliphile bilayers increases, as they are cultured at higher pH. In eukaryotes, cation leak inhibition is here attributed to sterols and certain isoprenes, dolichol for lysosomes and peroxysomes, ubiquinone for these in addition to mitochondrion, and plastoquinone for the chloroplast. Phytosterols differ from cholesterol because they contain methyl and ethyl branches on the side chain. The proposal provides a structure-function rationale for distinguishing the structures of the phytosterols as inhibitors of proton leaks from that of cholesterol which is proposed to inhibit leaks of Na(+). The most extensively studied of sterols, cholesterol, occurs only in animal cells where there is a sodium gradient across the plasma membrane. In mammals, nearly 100 proteins participate in cholesterol's biosynthetic and degradation pathway, its regulatory mechanisms and cell-delivery system. Although a fat, cholesterol yields no energy on degradation. Experiments have shown that it reduces Na(+) and K(+) leakage through lipid bilayers to approximately one third of bilayers that lack the sterol. If sterols significantly inhibit cation leakage through the lipids of the plasma membrane, then the general role of all sterols is to save metabolic ATP energy, which is the penalty for cation leaks into the cytosol. The regulation of cholesterol's appearance in the plasma membrane and the evolution of sterols is discussed in light of this proposed role.
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Affiliation(s)
- T H Haines
- Department of Chemistry, City College of the City University of New York and Biochemistry, City University of New York Medical School, New York, NY 10031, USA.
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Reid LM, Nicol RW, Ouellet T, Savard M, Miller JD, Young JC, Stewart DW, Schaafsma AW. Interaction of Fusarium graminearum and F. moniliforme in Maize Ears: Disease Progress, Fungal Biomass, and Mycotoxin Accumulation. PHYTOPATHOLOGY 1999; 89:1028-1037. [PMID: 18944658 DOI: 10.1094/phyto.1999.89.11.1028] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT To investigate the interaction between two major ear-rotting pathogens, maize ears were inoculated with either Fusarium graminearum, F. moniliforme, or an equal mixture of the two. Silk and kernel tissues were periodically harvested throughout the growing season so that a time course of the experimental variables (disease severity, ergosterol content, fungal DNA content, and mycotoxin concentration) could be recorded. Over the 3 years tested (1992 to 1994), the highest levels of disease and ergosterol were found in the F. graminearum treatment, followed by the mixture treatment (F. graminearum plus F. moniliforme) and, finally, the F. moniliforme treatment. Kernel ergosterol content and disease rating were correlated for both pathogens, but the highest correlation coefficients were obtained in the F. graminearum treatment. The DNA analysis revealed that, in the mixed inoculum, F. moniliforme had a greater growth rate than did F. graminearum. In 1994, appreciable F. moniliforme from natural inoculum was found in the F. graminearum treatment. Fumonisin B(1) levels did not differ between the F. moniliforme treatment and the mixed inoculum treatment. The effect of temperature on the growth rate of the two species explained some of the field results, with temperatures in the silks being more favorable to F. moniliforme. Data on the growth rate on silks obtained by the incorporation of radiolabeled precursor to ergosterol demonstrated that F. graminearum was able to grow well at 26 to 28 degrees C, whereas F. moniliforme grew well over a broader range, including at higher temperatures.
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Bellamine A, Mangla AT, Nes WD, Waterman MR. Characterization and catalytic properties of the sterol 14alpha-demethylase from Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 1999; 96:8937-42. [PMID: 10430874 PMCID: PMC17711 DOI: 10.1073/pnas.96.16.8937] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sterol 14alpha-demethylase encoded by CYP51 is a mixed-function oxidase involved in sterol synthesis in eukaryotic organisms. Completion of the Mycobacterium tuberculosis genome project revealed that a protein having homology to mammalian 14alpha-demethylases might be present in this bacterium. Using genomic DNA from mycobacterial strain H(37)Rv, we have established unambiguously that the CYP51-like gene encodes a bacterial sterol 14alpha-demethylase. Expression of the M. tuberculosis CYP51 gene in Escherichia coli yields a P450, which, when purified to homogeneity, has the predicted molecular mass, ca. 50 kDa on SDS/PAGE, and binds both sterol substrates and azole inhibitors of P450 14alpha-demethylases. It catalyzes 14alpha-demethylation of lanosterol, 24, 25-dihydrolanosterol, and obtusifoliol to produce the 8,14-dienes stereoselectively as shown by GC/MS and (1)H NMR analysis. Both flavodoxin and ferredoxin redox systems are able to support this enzymatic activity. Structural requirements of a 14alpha-methyl group and Delta(8(9))-bond were established by comparing binding of pairs of sterol substrate that differed in a single molecular feature, e.g., cycloartenol paired with lanosterol. These substrate requirements are similar to those established for plant and animal P450 14alpha-demethylases. From the combination of results, the interrelationships of substrate functional groups within the active site show that oxidative portions of the sterol biosynthetic pathway are present in prokaryotes.
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Affiliation(s)
- A Bellamine
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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Pal D, Banerjee D, Patra TK, Patra A, Ghosh A. Liver lipids and fatty acids of the sting ray Dasyatis bleekeri
(Blyth). J AM OIL CHEM SOC 1998. [DOI: 10.1007/s11746-998-0185-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Debasish Pal
- ; Department of Chemistry; Bose Institute; 93/1, Acharya Prafulla Chandra Road 700009 Calcutta India
| | - Dipankar Banerjee
- ; Department of Chemistry; Bose Institute; 93/1, Acharya Prafulla Chandra Road 700009 Calcutta India
| | - Tarun K. Patra
- ; Department of Chemistry; Bose Institute; 93/1, Acharya Prafulla Chandra Road 700009 Calcutta India
| | - Amarendra Patra
- ; CAS on Natural Products, Department of Chemistry, College of Science & Technology; University of Calcutta; 700009 Calcutta India
| | - Amitabha Ghosh
- ; Department of Chemistry; Bose Institute; 93/1, Acharya Prafulla Chandra Road 700009 Calcutta India
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Sein KK, Aikawa M. The prime role of plasma membrane cholesterol in the pathogenesis of immune evasion and clinical manifestations of falciparum malaria. Med Hypotheses 1998; 51:105-10. [PMID: 9881815 DOI: 10.1016/s0306-9877(98)90102-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The pathogenesis of falciparum malaria, with its immune evasion, mechanism of immune suppression and immunological inertia, the cause of its preferential incidence in children and pregnant mothers, and the pathological basis of clinical manifestations, are discussed from biochemical, biophysical and immunological perspectives. Sequestration and recrudescence are highlighted as the evolved means by which malaria parasites survive. These discussions are based on a novel hypothesis that changes in the lipid matrix fluidity of plasma membrane, through alterations of cholesterol and phospholipid content and variation in body temperature, significantly affect the membrane functions of cells. The pathogenesis of aggressive behavior in cerebral malaria is postulated to be different from that of coma, and complicated pregnancy in malaria is also discussed as a multifactorial condition wherein hypocholesterolemia, resulting from increased membrane biogenesis of multiplying parasites, is the common underlying factor.
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Affiliation(s)
- K K Sein
- Department of Pathology, Institute of Medicine, Mandalay, Myanmar
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50
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Ohvo H, Olsio C, Slotte JP. Effects of sphingomyelin and phosphatidylcholine degradation on cyclodextrin-mediated cholesterol efflux in cultured fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1349:131-41. [PMID: 9421186 DOI: 10.1016/s0005-2760(97)00126-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The hydrolysis of plasma membrane sphingomyelin is known to dramatically alter cellular cholesterol homeostasis in different ways, whereas the degradation of plasma membrane phosphatidylcholine has much less or no effects on cell cholesterol homeostasis [Pörn, Ares, Slotte, J. Lipid Res. 34 (1993) 1385-1392]. In this study, we used an efficient extracellular cholesterol acceptor (cyclodextrin) and determined the extent of cholesterol efflux from cultured fibroblasts in which plasma membrane sphingomyelin or phosphatidylcholine was degraded. Treatment of cells with sphingomyelinase reduced the cell sphingomyelin content by about 76% (about 13 nmol SM degraded), and dramatically increased the desorption of [3H]cholesterol from the plasma membrane to 2-hydroxypropyl-beta-cyclodextrin. The corresponding hydrolysis of cell surface phosphatidylcholine (about 12% reduction of the cellular phosphatidylcholine content, corresponding to about 12 nmol degraded PC) had almost no effect on cell [3H]cholesterol efflux. The stimulatory effect of sphingomyelin degradation on cell [3H]cholesterol efflux was reversible, since rates of [3H]cholesterol efflux dropped back to control levels when cells (in this case baby hamster kidney cells) were allowed to restore their sphingomyelin content by re-synthesis in the absence of sphingomyelinase. The findings of this study clearly demonstrate that plasma membrane sphingomyelin markedly affected the rate of cholesterol transfer between cells and an extracellular acceptor (i.e., cyclodextrin), whereas the effect of phosphatidylcholine on cholesterol efflux was much smaller.
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Affiliation(s)
- H Ohvo
- Department of Biochemistry and Pharmacy, Abo Akademi University, Turku, Finland.
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