1
|
Evidence for Electron Transfer from the Bidirectional Hydrogenase to the Photosynthetic Complex I (NDH-1) in the Cyanobacterium Synechocystis sp. PCC 6803. Microorganisms 2022; 10:microorganisms10081617. [PMID: 36014035 PMCID: PMC9414918 DOI: 10.3390/microorganisms10081617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 12/12/2022] Open
Abstract
The cyanobacterial bidirectional [NiFe]-hydrogenase is a pentameric enzyme. Apart from the small and large hydrogenase subunits (HoxYH) it contains a diaphorase module (HoxEFU) that interacts with NAD(P)+ and ferredoxin. HoxEFU shows strong similarity to the outermost subunits (NuoEFG) of canonical respiratory complexes I. Photosynthetic complex I (NDH-1) lacks these three subunits. This led to the idea that HoxEFU might interact with NDH-1 instead. HoxEFUYH utilizes excited electrons from PSI for photohydrogen production and it catalyzes the reverse reaction and feeds electrons into the photosynthetic electron transport. We analyzed hydrogenase activity, photohydrogen evolution and hydrogen uptake, the respiration and photosynthetic electron transport of ΔhoxEFUYH, and a knock-out strain with dysfunctional NDH-1 (ΔndhD1/ΔndhD2) of the cyanobacterium Synechocystis sp. PCC 6803. Photohydrogen production was prolonged in ΔndhD1/ΔndhD2 due to diminished hydrogen uptake. Electrons from hydrogen oxidation must follow a different route into the photosynthetic electron transport in this mutant compared to wild type cells. Furthermore, respiration was reduced in ΔhoxEFUYH and the ΔndhD1/ΔndhD2 localization of the hydrogenase to the membrane was impaired. These data indicate that electron transfer from the hydrogenase to the NDH-1 complex is either direct, by the binding of the hydrogenase to the complex, or indirect, via an additional mediator.
Collapse
|
2
|
Xiong BJ, Dusny C, Wang L, Appel J, Lindstaedt K, Schlosser D, Harms H, Wick LY. Illuminate the hidden: in vivo mapping of microscale pH in the mycosphere using a novel whole-cell biosensor. ISME COMMUNICATIONS 2021; 1:75. [PMID: 36765263 PMCID: PMC9723660 DOI: 10.1038/s43705-021-00075-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 01/07/2023]
Abstract
The pH of an environment is both a driver and the result of diversity and functioning of microbial habitats such as the area affected by fungal hyphae (mycosphere). Here we used a novel pH-sensitive bioreporter, Synechocystis sp. PCC6803_peripHlu, and ratiometric fluorescence microscopy, to spatially and temporally resolve the mycosphere pH at the micrometre scale. Hyphae of the basidiomycete Coprionopsis cinerea were allowed to overgrow immobilised and homogeneously embedded pH bioreporters in an agarose microcosm. Signals of >700 individual cells in an area of 0.4 × 0.8 mm were observed over time and used to create highly resolved (3 × 3 µm) pH maps using geostatistical approaches. C. cinerea changed the pH of the agarose from 6.9 to ca. 5.0 after 48 h with hyphal tips modifying pH in their vicinity up to 1.8 mm. pH mapping revealed distinct microscale spatial variability and temporally stable gradients between pH 4.4 and 5.8 over distances of ≈20 µm. This is the first in vivo mapping of a mycosphere pH landscape at the microscale. It underpins the previously hypothesised establishment of pH gradients serving to create spatially distinct mycosphere reaction zones.
Collapse
Affiliation(s)
- Bi-Jing Xiong
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany
| | - Christian Dusny
- Department of Solar Materials, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany
| | - Lin Wang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Jens Appel
- Department of Biology, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 5, 24118, Kiel, Germany
| | - Kristin Lindstaedt
- Department of Solar Materials, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany
| | - Dietmar Schlosser
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany
| | - Hauke Harms
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany
| | - Lukas Y Wick
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Permoserstraβe 15, 04318, Leipzig, Germany.
| |
Collapse
|
3
|
Biosorption of Zn(II) from Seawater Solution by the Microalgal Biomass of Tetraselmis marina AC16-MESO. Int J Mol Sci 2021; 22:ijms222312799. [PMID: 34884601 PMCID: PMC8657923 DOI: 10.3390/ijms222312799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 02/06/2023] Open
Abstract
Biosorption refers to a physicochemical process where substances are removed from the solution by a biological material (live or dead) via adsorption processes governed by mechanisms such as surface complexation, ion exchange, and precipitation. This study aimed to evaluate the adsorption of Zn2+ in seawater using the microalgal biomass of Tetraselmis marina AC16-MESO “in vivo” and “not alive” at different concentrations of Zn2+ (0, 5, 10, and 20 mg L−1) at 72 h. Analysis was carried out by using the Langmuir isotherms and by evaluating the autofluorescence from microalgae. The maximum adsorption of Zn2+ by the Langmuir model using the Qmax parameter in the living microalgal biomass (Qmax = 0.03051 mg g−1) was more significant than the non-living microalgal biomass of T. marine AC16-MESO (Qmax = 0.02297 mg g−1). Furthermore, a decrease in fluorescence was detected in cells from T. marina AC16-MESO, in the following order: Zn2+ (0 < 20 < 5 < 10) mg L−1. Zn2+ was adsorbed quickly by living cells from T. marine AC16-MESO compared to the non-living microalgal biomass, with a decrease in photosystem II activities from 0 to 20 mg L−1 Zn2+ in living cells.
Collapse
|
4
|
Xu X, Ouyang M, Lu D, Zheng C, Zhang L. Protein Sorting within Chloroplasts. Trends Cell Biol 2020; 31:9-16. [PMID: 33121860 DOI: 10.1016/j.tcb.2020.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/22/2020] [Accepted: 09/30/2020] [Indexed: 12/11/2022]
Abstract
Chloroplasts have multiple suborganellar membranes. Correct and efficient translocation of chloroplast proteins from their site of synthesis into or across membranes to their functional compartments are fundamental processes. In recent years, several new components and regulatory mechanisms involved in chloroplast protein import and sorting have been explored. Moreover, the formation of liquid-liquid phase transition (LLPT) has been recently reported as a novel mechanism for regulating chloroplast protein sorting. Here, we overview the recent advances of both nuclear- and chloroplast-encoded protein trafficking to their final destination within chloroplasts, and discuss the novel components and regulatory mechanisms of intrachloroplast sorting. Furthermore, we propose that LLPT may be a universal and conserved mechanism for driving organelle protein trafficking and organelle biogenesis.
Collapse
Affiliation(s)
- Xiumei Xu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Jinming Avenue, Kaifeng 475004, China
| | - Min Ouyang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Dandan Lu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Jinming Avenue, Kaifeng 475004, China
| | - Canhui Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Jinming Avenue, Kaifeng 475004, China
| | - Lixin Zhang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Jinming Avenue, Kaifeng 475004, China.
| |
Collapse
|
5
|
Russo DA, Zedler JAZ. Genomic insights into cyanobacterial protein translocation systems. Biol Chem 2020; 402:39-54. [PMID: 33544489 DOI: 10.1515/hsz-2020-0247] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/25/2020] [Indexed: 02/07/2023]
Abstract
Cyanobacteria are ubiquitous oxygenic photosynthetic bacteria with a versatile metabolism that is highly dependent on effective protein targeting. Protein sorting in diderm bacteria is not trivial and, in cyanobacteria, even less so due to the presence of a complex membrane system: the outer membrane, the plasma membrane and the thylakoid membrane. In cyanobacteria, protein import into the thylakoids is essential for photosynthesis, export to the periplasm fulfills a multifunctional role in maintaining cell homeostasis, and secretion mediates motility, DNA uptake and environmental interactions. Intriguingly, only one set of genes for the general secretory and the twin-arginine translocation pathways seem to be present. However, these systems have to operate in both plasma and thylakoid membranes. This raises the question of how substrates are recognized and targeted to their correct, final destination. Additional complexities arise when a protein has to be secreted across the outer membrane, where very little is known regarding the mechanisms involved. Given their ecological importance and biotechnological interest, a better understanding of protein targeting in cyanobacteria is of great value. This review will provide insights into the known knowns of protein targeting, propose hypotheses based on available genomic sequences and discuss future directions.
Collapse
Affiliation(s)
- David A Russo
- Bioorganic Analytics, Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, D-07743 Jena, Germany
| | - Julie A Z Zedler
- Matthias Schleiden Institute for Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Dornburgerstr. 159, D-07743 Jena, Germany
| |
Collapse
|
6
|
Russo DA, Zedler JAZ, Wittmann DN, Möllers B, Singh RK, Batth TS, van Oort B, Olsen JV, Bjerrum MJ, Jensen PE. Expression and secretion of a lytic polysaccharide monooxygenase by a fast-growing cyanobacterium. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:74. [PMID: 30976324 PMCID: PMC6442416 DOI: 10.1186/s13068-019-1416-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/21/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND Cyanobacteria have the potential to become next-generation cell factories due to their ability to use CO2, light and inorganic nutrients to produce a range of biomolecules of commercial interest. Synechococcus elongatus UTEX 2973, in particular, is a fast-growing, genetically tractable, cyanobacterium that has garnered attention as a potential biotechnological chassis. To establish this unique strain as a host for heterologous protein production, we aimed to demonstrate expression and secretion of the industrially relevant TfAA10A, a lytic polysaccharide monooxygenase from the Gram-positive bacterium Thermobifida fusca. RESULTS Two variations of TfAA10A were successfully expressed in S. elongatus UTEX 2973: One containing the native N-terminal, Sec-targeted, signal peptide and a second with a Tat-targeted signal peptide from the Escherichia coli trimethylamine-N-oxide reductase (TorA). Although the TorA signal peptide correctly targeted the protein to the plasma membrane, the majority of the TorA-TfAA10A was found unprocessed in the plasma membrane with a small fraction of the mature protein ultimately translocated to the periplasm. The native Sec signal peptide allowed for efficient secretion of TfAA10A into the medium with virtually no protein being found in the cytosol, plasma membrane or periplasm. TfAA10A was demonstrated to be correctly cleaved and active on the model substrate phosphoric acid swollen cellulose. Additionally, expression and secretion only had a minor impact on cell growth. The secretion yield was estimated at 779 ± 40 µg L-1 based on densitometric analysis. To our knowledge, this is the highest secretion yield ever registered in cyanobacteria. CONCLUSIONS We have shown for the first time high-titer expression and secretion of an industrially relevant and catalytically active enzyme in S. elongatus UTEX 2973. This proof-of-concept study will be valuable for the development of novel and sustainable applications in the fields of bioremediation and biocatalysis.
Collapse
Affiliation(s)
- D. A. Russo
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - J. A. Z. Zedler
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - D. N. Wittmann
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - B. Möllers
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - R. K. Singh
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - T. S. Batth
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - B. van Oort
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - J. V. Olsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M. J. Bjerrum
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - P. E. Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| |
Collapse
|
7
|
Polyviou D, Machelett MM, Hitchcock A, Baylay AJ, MacMillan F, Moore CM, Bibby TS, Tews I. Structural and functional characterization of IdiA/FutA (Tery_3377), an iron-binding protein from the ocean diazotroph Trichodesmium erythraeum. J Biol Chem 2018; 293:18099-18109. [PMID: 30217820 PMCID: PMC6254336 DOI: 10.1074/jbc.ra118.001929] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/31/2018] [Indexed: 11/17/2022] Open
Abstract
Atmospheric nitrogen fixation by photosynthetic cyanobacteria (diazotrophs) strongly influences oceanic primary production and in turn affects global biogeochemical cycles. Species of the genus Trichodesmium are major contributors to marine diazotrophy, accounting for a significant proportion of the fixed nitrogen in tropical and subtropical oceans. However, Trichodesmium spp. are metabolically constrained by the availability of iron, an essential element for both the photosynthetic apparatus and the nitrogenase enzyme. Survival strategies in low-iron environments are typically poorly characterized at the molecular level, because these bacteria are recalcitrant to genetic manipulation. Here, we studied a homolog of the iron deficiency-induced A (IdiA)/ferric uptake transporter A (FutA) protein, Tery_3377, which has been used as an in situ iron-stress biomarker. IdiA/FutA has an ambiguous function in cyanobacteria, with its homologs hypothesized to be involved in distinct processes depending on their cellular localization. Using signal sequence fusions to GFP and heterologous expression in the model cyanobacterium Synechocystis sp. PCC 6803, we show that Tery_3377 is targeted to the periplasm by the twin-arginine translocase and can complement the deletion of the native Synechocystis ferric-iron ABC transporter periplasmic binding protein (FutA2). EPR spectroscopy revealed that purified recombinant Tery_3377 has specificity for iron in the Fe3+ state, and an X-ray crystallography–determined structure uncovered a functional iron substrate–binding domain, with Fe3+ pentacoordinated by protein and buffer ligands. Our results support assignment of Tery_3377 as a functional FutA subunit of an Fe3+ ABC transporter but do not rule out dual IdiA function.
Collapse
Affiliation(s)
- Despo Polyviou
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Moritz M Machelett
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom,; the Department of Biological Sciences, Faculty of Natural and Environmental Sciences, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom, and
| | - Andrew Hitchcock
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Alison J Baylay
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Fraser MacMillan
- the School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - C Mark Moore
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Thomas S Bibby
- From the Ocean and Earth Sciences, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Ivo Tews
- the Department of Biological Sciences, Faculty of Natural and Environmental Sciences, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom, and.
| |
Collapse
|
8
|
Schuergers N, Lenn T, Kampmann R, Meissner MV, Esteves T, Temerinac-Ott M, Korvink JG, Lowe AR, Mullineaux CW, Wilde A. Cyanobacteria use micro-optics to sense light direction. eLife 2016; 5:12620. [PMID: 26858197 PMCID: PMC4758948 DOI: 10.7554/elife.12620] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/26/2015] [Indexed: 01/08/2023] Open
Abstract
Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world's smallest and oldest example of a camera eye.
Collapse
Affiliation(s)
- Nils Schuergers
- Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Tchern Lenn
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Ronald Kampmann
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Markus V Meissner
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Tiago Esteves
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,INEB- Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.,Faculdade de Engenharia da Universidade do Porto, , Portugal
| | - Maja Temerinac-Ott
- Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
| | - Jan G Korvink
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alan R Lowe
- London Centre for Nanotechnology, London, United Kingdom.,Institute for Structural and Molecular Biology, University College London and Birkbeck College London, London, United Kingdom
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.,Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| |
Collapse
|
9
|
Kumari S, Chaurasia AK. In silico analysis and experimental validation of lipoprotein and novel Tat signal peptides processing in Anabaena sp. PCC7120. J Microbiol 2015; 53:837-46. [PMID: 26626354 DOI: 10.1007/s12275-015-5281-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022]
Abstract
Signal peptide (SP) plays a pivotal role in protein translocation. Lipoprotein- and twin arginine translocase (Tat) dependent signal peptides were studied in All3087, a homolog of competence protein of Synechocystis PCC6803 and in two putative alkaline phosphatases (ALPs, Alr2234 and Alr4976), respectively. In silico analysis of All3087 is shown to possess the characteristics feature of competence proteins such as helix-hairpin-helix, N and C-terminal HKD endonuclease domain, calcium binding domain and N-terminal lipoprotein signal peptide. The SP recognition-cleavage site in All3087 was predicted (AIA-AC) using SignalP while further in-depth analysis using Pred-Lipo and WebLogo analysis for consensus sequence showed it as IAA-C. Activities of putative ALPs were confirmed by heterologous overexpression, activity assessment and zymogram analysis. ALP activity in Anabaena remains cell bound in log-phase, but during late log/stationary phase, an enhanced ALP activity was detected in extracellular milieu. The enhancement of ALP activity during stationary phase was not only due to inorganic phosphate limitation but also contributed by the presence of novel bipartite Tat-SP. The Tat signal transported the folded active ALPs to the membrane, followed by anchoring into the membrane and successive cleavage enabling transportation of the ALPs to the extracellular milieu, because of bipartite architecture and processing of transit Tat-SP.
Collapse
Affiliation(s)
- Sonika Kumari
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
| | | |
Collapse
|
10
|
Inactivation of the Deg protease family in the cyanobacterium Synechocystis sp. PCC 6803 has impact on the outer cell layers. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 152:383-94. [DOI: 10.1016/j.jphotobiol.2015.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/12/2015] [Accepted: 05/15/2015] [Indexed: 12/13/2022]
|
11
|
Albers SC, Gallegos VA, Peebles CAM. Engineering of genetic control tools in Synechocystis sp. PCC 6803 using rational design techniques. J Biotechnol 2015; 216:36-46. [PMID: 26450561 DOI: 10.1016/j.jbiotec.2015.09.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/17/2015] [Accepted: 09/29/2015] [Indexed: 12/01/2022]
Abstract
Cyanobacteria show promise as photosynthetic microbial factories capable of harnessing sunlight and CO2 to produce valuable end products, but few genetic control tools have been characterized and utilized in these organisms. To develop a suite of control elements capable of gene control at a variety of expression strengths, a library of 10 promoter-constructs were developed and built via rational design techniques by adding individual nucleotides in a step-wise manner within the -10 and -35 cis-acting regions of the tac promoter. This suite produced a dynamic range of expression strength, exhibiting a 78 fold change between the lowest expressing promoter, Psca8- and the highest expressing promoter, Psca3-2 when tested within Synechocystis sp. PCC 6803. Additionally, this study details the construction of a chemically inducible construct for use in Synechocystis that is based on the tac repressor system most commonly used in Escherichia coli. This research demonstrates the construction of a highly expressed inducible promoter that is also capable of high levels of gene repression. Upon chemical induction with IPTG, this same mutant strain was capable of exhibiting an average 24X increase in GFP expression over that of the repressed state.
Collapse
Affiliation(s)
- Stevan C Albers
- Cell and Molecular Biology Graduate Program, Colorado State University, 1005 Campus Delivery, Fort Collins, CO 80523, USA.
| | - Victor A Gallegos
- Department of Biochemistry and Molecular Biology, Colorado State University, 1870 Campus Delivery, Fort Collins, CO 80523, USA; Department of Chemical and Biological Engineering, Colorado State University, 1370 Campus Delivery, Fort Collins, CO 80523, USA.
| | - Christie A M Peebles
- Cell and Molecular Biology Graduate Program, Colorado State University, 1005 Campus Delivery, Fort Collins, CO 80523, USA; Department of Chemical and Biological Engineering, Colorado State University, 1370 Campus Delivery, Fort Collins, CO 80523, USA.
| |
Collapse
|
12
|
Frain KM, Gangl D, Jones A, Zedler JAZ, Robinson C. Protein translocation and thylakoid biogenesis in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:266-73. [PMID: 26341016 DOI: 10.1016/j.bbabio.2015.08.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/17/2015] [Accepted: 08/31/2015] [Indexed: 10/23/2022]
Abstract
Cyanobacteria exhibit a complex form of membrane differentiation that sets them apart from most bacteria. Many processes take place in the plasma membrane, but photosynthetic light capture, electron transport and ATP synthesis take place in an abundant internal thylakoid membrane. This review considers how this system of subcellular compartmentalisation is maintained, and how proteins are directed towards the various subcompartments--specifically the plasma membrane, periplasm, thylakoid membrane and thylakoid lumen. The involvement of Sec-, Tat- and signal recognition particle- (SRP)-dependent protein targeting pathways is discussed, together with the possible involvement of a so-called 'spontaneous' pathway for the insertion of membrane proteins, previously characterised for chloroplast thylakoid membrane proteins. An intriguing aspect of cyanobacterial cell biology is that most contain only a single set of genes encoding Sec, Tat and SRP components, yet the proteomes of the plasma and thylakoid membranes are very different. The implications for protein sorting mechanisms are considered. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Prof Conrad Mullineaux.
Collapse
Affiliation(s)
- Kelly M Frain
- Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom
| | - Doris Gangl
- Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom
| | - Alexander Jones
- Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom
| | - Julie A Z Zedler
- Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom
| | - Colin Robinson
- Centre for Molecular Processing, School of Biosciences, University of Kent, Ingram Building, Canterbury, CT2 7NJ, United Kingdom.
| |
Collapse
|
13
|
Plohnke N, Seidel T, Kahmann U, Rögner M, Schneider D, Rexroth S. The proteome and lipidome of Synechocystis sp. PCC 6803 cells grown under light-activated heterotrophic conditions. Mol Cell Proteomics 2015; 14:572-84. [PMID: 25561504 PMCID: PMC4349978 DOI: 10.1074/mcp.m114.042382] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/10/2014] [Indexed: 12/31/2022] Open
Abstract
Cyanobacteria are photoautotrophic prokaryotes with a plant-like photosynthetic machinery. Because of their short generation times, the ease of their genetic manipulation, and the limited size of their genome and proteome, cyanobacteria are popular model organisms for photosynthetic research. Although the principal mechanisms of photosynthesis are well-known, much less is known about the biogenesis of the thylakoid membrane, hosting the components of the photosynthetic, and respiratory electron transport chain in cyanobacteria. Here we present a detailed proteome analysis of the important model and host organism Synechocystis sp. PCC 6803 under light-activated heterotrophic growth conditions. Because of the mechanistic importance and severe changes in thylakoid membrane morphology under light-activated heterotrophic growth conditions, a focus was put on the analysis of the membrane proteome, which was supported by a targeted lipidome analysis. In total, 1528 proteins (24.5% membrane integral) were identified in our analysis. For 641 of these proteins quantitative information was obtained by spectral counting. Prominent changes were observed for proteins associated with oxidative stress response and protein folding. Because of the heterotrophic growth conditions, also proteins involved in carbon metabolism and C/N-balance were severely affected. Although intracellular thylakoid membranes were significantly reduced, only minor changes were observed in their protein composition. The increased proportion of the membrane-stabilizing sulfoqinovosyl diacyl lipids found in the lipidome analysis, as well as the increased content of lipids with more saturated acyl chains, are clear indications for a coordinated synthesis of proteins and lipids, resulting in stabilization of intracellular thylakoid membranes under stress conditions.
Collapse
Affiliation(s)
- Nicole Plohnke
- From the ‡Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Tobias Seidel
- §Department of Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Uwe Kahmann
- ¶Department of Molecular Cell Biology, Bielefeld University, 33615 Bielefeld, Germany
| | - Matthias Rögner
- From the ‡Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Dirk Schneider
- §Department of Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany;
| | - Sascha Rexroth
- From the ‡Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr-University Bochum, 44780 Bochum, Germany;
| |
Collapse
|
14
|
Comparative Mechanisms of Protein Transduction Mediated by Cell-Penetrating Peptides in Prokaryotes. J Membr Biol 2015; 248:355-68. [DOI: 10.1007/s00232-015-9777-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/23/2015] [Indexed: 10/24/2022]
|
15
|
Burroughs NJ, Boehm M, Eckert C, Mastroianni G, Spence EM, Yu J, Nixon PJ, Appel J, Mullineaux CW, Bryan SJ. Solar powered biohydrogen production requires specific localization of the hydrogenase. ENERGY & ENVIRONMENTAL SCIENCE 2014; 7:3791-3800. [PMID: 26339289 PMCID: PMC4535174 DOI: 10.1039/c4ee02502d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/04/2014] [Indexed: 05/15/2023]
Abstract
Cyanobacteria contain a bidirectional [NiFe] hydrogenase which transiently produces hydrogen upon exposure of anoxic cells to light, potentially acting as a "valve" releasing excess electrons from the electron transport chain. However, its interaction with the photosynthetic electron transport chain remains unclear. By GFP-tagging the HoxF diaphorase subunit we show that the hydrogenase is thylakoid associated, comprising a population dispersed uniformly through the thylakoids and a subpopulation localized to discrete puncta in the distal thylakoid. Thylakoid localisation of both the HoxH and HoxY hydrogenase subunits is confirmed by immunogold electron microscopy. The diaphorase HoxE subunit is essential for recruitment to the dispersed thylakoid population, potentially anchoring the hydrogenase to the membrane, but aggregation to puncta occurs through a distinct HoxE-independent mechanism. Membrane association does not require NDH-1. Localization is dynamic on a scale of minutes, with anoxia and high light inducing a significant redistribution between these populations in favour of puncta. Since HoxE is essential for access to its electron donor, electron supply to the hydrogenase depends on a physiologically controlled localization, potentially offering a new avenue to enhance photosynthetic hydrogen production by exploiting localization/aggregation signals.
Collapse
Affiliation(s)
- Nigel J Burroughs
- Systems Biology Centre , Coventry House , University of Warwick , Coventry , CV4 7AL , UK
| | - Marko Boehm
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Carrie Eckert
- Biosciences Centre , National Renewable Energy Laboratory , Golden , Colorado 80401 , USA ; Renewable and Sustainable Energy Institute, University of Colorado Boulder , Boulder , CO 80309 , USA
| | - Giulia Mastroianni
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
| | - Edward M Spence
- Pharmaceutical Science Division , King's College London , Franklin-Wilkins Building, 150 Stamford Street , London , SE1 9NH , UK
| | - Jianfeng Yu
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Peter J Nixon
- Imperial College London , South Kensington Campus , London , SW7 2AZ , UK
| | - Jens Appel
- Botanical Institute , University of Kiel , Am Botanischen Garten 1-9 , 24118 Kiel , Germany
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
| | - Samantha J Bryan
- School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , London , E1 4NS , UK .
| |
Collapse
|
16
|
Bryan SJ, Burroughs NJ, Shevela D, Yu J, Rupprecht E, Liu LN, Mastroianni G, Xue Q, Llorente-Garcia I, Leake MC, Eichacker LA, Schneider D, Nixon PJ, Mullineaux CW. Localisation and interactions of the Vipp1 protein in cyanobacteria. Mol Microbiol 2014; 94:1179-1195. [PMID: 25308470 PMCID: PMC4297356 DOI: 10.1111/mmi.12826] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2014] [Indexed: 12/22/2022]
Abstract
The Vipp1 protein is essential in cyanobacteria and chloroplasts for the maintenance of photosynthetic function and thylakoid membrane architecture. To investigate its mode of action we generated strains of the cyanobacteria Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 in which Vipp1 was tagged with green fluorescent protein at the C-terminus and expressed from the native chromosomal locus. There was little perturbation of function. Live-cell fluorescence imaging shows dramatic relocalisation of Vipp1 under high light. Under low light, Vipp1 is predominantly dispersed in the cytoplasm with occasional concentrations at the outer periphery of the thylakoid membranes. High light induces Vipp1 coalescence into localised puncta within minutes, with net relocation of Vipp1 to the vicinity of the cytoplasmic membrane and the thylakoid membranes. Pull-downs and mass spectrometry identify an extensive collection of proteins that are directly or indirectly associated with Vipp1 only after high-light exposure. These include not only photosynthetic and stress-related proteins but also RNA-processing, translation and protein assembly factors. This suggests that the Vipp1 puncta could be involved in protein assembly. One possibility is that Vipp1 is involved in the formation of stress-induced localised protein assembly centres, enabling enhanced protein synthesis and delivery to membranes under stress conditions.
Collapse
Affiliation(s)
- Samantha J Bryan
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Nigel J Burroughs
- Mathematics Institute and Warwick Systems Biology Centre, University of WarwickCoventry, CV4 7AL, UK
| | - Dmitriy Shevela
- Department of Mathematics and Natural Science, University of Stavanger4036, Stavanger, Norway
| | - Jianfeng Yu
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
| | - Eva Rupprecht
- Institut für Biochemie und Molekularbiologie, ZBMZ, Albert-Ludwigs-UniversitätStefan-Meier-Strasse 17, 79104, Freiburg, Germany
| | - Lu-Ning Liu
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Giulia Mastroianni
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| | - Quan Xue
- Clarendon Laboratory, Department of Physics, University of OxfordParks Road, Oxford, OX1 3PU, UK
| | - Isabel Llorente-Garcia
- Clarendon Laboratory, Department of Physics, University of OxfordParks Road, Oxford, OX1 3PU, UK
- Department of Physics and Astronomy, University College LondonGower St., London, WC1E 6BT, UK
| | - Mark C Leake
- Biological Physical Sciences Institute (BPSI), Departments of Physics and Biology, University of YorkYork, YO105DD, UK
| | - Lutz A Eichacker
- Department of Mathematics and Natural Science, University of Stavanger4036, Stavanger, Norway
| | - Dirk Schneider
- Institut für Biochemie und Molekularbiologie, ZBMZ, Albert-Ludwigs-UniversitätStefan-Meier-Strasse 17, 79104, Freiburg, Germany
- Institut für Pharmazie und Biochemie, Johannes Gutenberg-Universität Mainz55128, Mainz, Germany
| | - Peter J Nixon
- Department of Life Sciences, Imperial College LondonLondon, SW7 2AZ, UK
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of LondonMile End Road, London, E1 4NS, UK
| |
Collapse
|
17
|
Kaňa R. Mobility of photosynthetic proteins. PHOTOSYNTHESIS RESEARCH 2013; 116:465-79. [PMID: 23955784 DOI: 10.1007/s11120-013-9898-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/18/2013] [Indexed: 05/03/2023]
Abstract
The mobility of photosynthetic proteins represents an important factor that affects light-energy conversion in photosynthesis. The specific feature of photosynthetic proteins mobility can be currently measured in vivo using advanced microscopic methods, such as fluorescence recovery after photobleaching which allows the direct observation of photosynthetic proteins mobility on a single cell level. The heterogeneous organization of thylakoid membrane proteins results in heterogeneity in protein mobility. The thylakoid membrane contains both, protein-crowded compartments with immobile proteins and fluid areas (less crowded by proteins), allowing restricted diffusion of proteins. This heterogeneity represents an optimal balance as protein crowding is necessary for efficient light-energy conversion, and protein mobility plays an important role in the regulation of photosynthesis. The mobility is required for an optimal light-harvesting process (e.g., during state transitions), and also for transport of proteins during their synthesis or repair. Protein crowding is then a key limiting factor of thylakoid membrane protein mobility; the less thylakoid membranes are crowded by proteins, the higher protein mobility is observed. Mobility of photosynthetic proteins outside the thylakoid membrane (lumen and stroma/cytosol) is less understood. Cyanobacterial phycobilisomes attached to the stromal side of the thylakoid can move relatively fast. Therefore, it seems that stroma with their active enzymes of the Calvin-Benson cycle, are a more fluid compartment in comparison to the rather rigid thylakoid lumen. In conclusion, photosynthetic protein diffusion is generally slower in comparison to similarly sized proteins from other eukaryotic membranes or organelles. Mobility of photosynthetic proteins resembles restricted protein diffusion in bacteria, and has been rationalized by high protein crowding similar to that of thylakoids.
Collapse
Affiliation(s)
- Radek Kaňa
- Department of photothrophic microorganisms - Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81, Třeboň, Czech Republic,
| |
Collapse
|
18
|
Chungjatupornchai W, Fa-Aroonsawat S. The rrnA promoter as a tool for the improved expression of heterologous genes in cyanobacteria. Microbiol Res 2013; 169:361-8. [PMID: 24140155 DOI: 10.1016/j.micres.2013.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/02/2013] [Accepted: 09/15/2013] [Indexed: 11/28/2022]
Abstract
The regulatory sequence of ribosomal RNA A (rrnA) operon from Synechococcus PCC7942 was characterized using green fluorescent protein gene (gfp) as a reporter. The PR promoter (nt. -83 to +2) including upstream promoter element and P1 promoter of rrnA exhibited GFP fluorescence intensity about 30-fold higher than full length sequence (nt. -147 to +79). The effects of PR promoter arranged in tandem with consensus-σ(70) promoter (PS) of Escherichia coli on the expression of gfp and opd gene encoding organophosphorus hydrolase (OPH) in Synechococcus were investigated. The PS-PR tandem promoter was superior to all of the other promoters; its GFP fluorescence intensity was a 1.8-fold increase when compared to PR-PR tandem promoter, a 2.5-fold, 9.5-fold and a 15-fold increase compared to PR, PS and promoter of tRNA(pro), respectively. The GFP from PS-PR tandem promoter accounted for about 12% of its total extracted proteins. OPH activity of Synechococcus harboring opd gene under the control of PS-PR tandem promoter was 738 ± 128 units/OD₇₃₀. We demonstrated that the tandem promoters remarkably enhanced the GFP and OPH production which were detected on SDS-PAGE stained with Coomassie blue. The promoter system in this study could be generally applied to production of valuable organic products from cyanobacteria.
Collapse
Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| |
Collapse
|
19
|
Exploring the size limit of protein diffusion through the periplasm in cyanobacterium Anabaena sp. PCC 7120 using the 13 kDa iLOV fluorescent protein. Res Microbiol 2013; 164:710-7. [DOI: 10.1016/j.resmic.2013.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 05/24/2013] [Indexed: 01/16/2023]
|
20
|
Zhang L, Selão TT, Pisareva T, Qian J, Sze SK, Carlberg I, Norling B. Deletion of Synechocystis sp. PCC 6803 leader peptidase LepB1 affects photosynthetic complexes and respiration. Mol Cell Proteomics 2013; 12:1192-203. [PMID: 23358502 DOI: 10.1074/mcp.m112.022145] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The cyanobacterium Synechocystis sp. PCC 6803 possesses two leader peptidases, LepB1 (Sll0716) and LepB2 (Slr1377), responsible for the processing of signal peptide-containing proteins. Deletion of the gene for LepB1 results in an inability to grow photoautotrophically and an extreme light sensitivity. Here we show, using a combination of Blue Native/SDS-PAGE, Western blotting and iTRAQ analysis, that lack of LepB1 strongly affects the cell's ability to accumulate wild-type levels of both photosystem I (PSI) and cytochrome (Cyt) b6f complexes. The impaired assembly of PSI and Cyt b6f is considered to be caused by the no or slow processing of the integral subunits PsaF and Cyt f respectively. In particular, PsaF, one of the PSI subunits, was found incorporated into PSI in its unprocessed form, which could influence the assembly and/or stability of PSI. In contrast to these results, we found the amount of assembled photosystem II (PSII) unchanged, despite a slower processing of PsbO. Thus, imbalance in the ratios of PSI and Cyt b6f to photosystem II leads to an imbalanced photosynthetic electron flow up- and down-stream of the plastoquinone pool, resulting in the observed light sensitivity of the mutant. We conclude that LepB1 is the natural leader peptidase for PsaF, PsbO, and Cyt f. The maturation of PsbO and Cyt f can be partially performed by LepB2, whereas PsaF processing is completely dependent on LepB1. iTRAQ analysis also revealed a number of indirect effects accompanying the mutation, primarily a strong induction of the CydAB oxidase as well as a significant decrease in phycobiliproteins and chlorophyll/heme biosynthesis enzymes.
Collapse
Affiliation(s)
- Lifang Zhang
- Nanyang Technological University, School of Biological Sciences, 637551 Singapore
| | | | | | | | | | | | | |
Collapse
|
21
|
Degradation of PsbO by the Deg protease HhoA Is thioredoxin dependent. PLoS One 2012; 7:e45713. [PMID: 23029195 PMCID: PMC3446894 DOI: 10.1371/journal.pone.0045713] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 08/24/2012] [Indexed: 02/02/2023] Open
Abstract
The widely distributed members of the Deg/HtrA protease family play an important role in the proteolysis of misfolded and damaged proteins. Here we show that the Deg protease rHhoA is able to degrade PsbO, the extrinsic protein of the Photosystem II (PSII) oxygen-evolving complex in Synechocystis sp. PCC 6803 and in spinach. PsbO is known to be stable in its oxidized form, but after reduction by thioredoxin it became a substrate for recombinant HhoA (rHhoA). rHhoA cleaved reduced eukaryotic (specifically, spinach) PsbO at defined sites and created distinct PsbO fragments that were not further degraded. As for the corresponding prokaryotic substrate (reduced PsbO of Synechocystis sp. PCC 6803), no PsbO fragments were observed. Assembly to PSII protected PsbO from degradation. For Synechocystis sp. PCC 6803, our results show that HhoA, HhoB, and HtrA are localized in the periplasma and/or at the thylakoid membrane. In agreement with the idea that PsbO could be a physiological substrate for Deg proteases, part of the cellular fraction of the three Deg proteases of Synechocystis sp. PCC 6803 (HhoA, HhoB, and HtrA) was detected in the PSII-enriched membrane fraction.
Collapse
|
22
|
Changes in membrane lipids and carotenoids during light acclimation in a marine cyanobacterium Synechococcus sp. J Biosci 2012; 37:635-45. [DOI: 10.1007/s12038-012-9234-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|
23
|
Control of electron transport routes through redox-regulated redistribution of respiratory complexes. Proc Natl Acad Sci U S A 2012; 109:11431-6. [PMID: 22733774 DOI: 10.1073/pnas.1120960109] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In cyanobacteria, respiratory electron transport takes place in close proximity to photosynthetic electron transport, because the complexes required for both processes are located within the thylakoid membranes. The balance of electron transport routes is crucial for cell physiology, yet the factors that control the predominance of particular pathways are poorly understood. Here we use a combination of tagging with green fluorescent protein and confocal fluorescence microscopy in live cells of the cyanobacterium Synechococcus elongatus PCC 7942 to investigate the distribution on submicron scales of two key respiratory electron donors, type-I NAD(P)H dehydrogenase (NDH-1) and succinate dehydrogenase (SDH). When cells are grown under low light, both complexes are concentrated in discrete patches in the thylakoid membranes, about 100-300 nm in diameter and containing tens to hundreds of complexes. Exposure to moderate light leads to redistribution of both NDH-1 and SDH such that they become evenly distributed within the thylakoid membranes. The effects of electron transport inhibitors indicate that redistribution of respiratory complexes is triggered by changes in the redox state of an electron carrier close to plastoquinone. Redistribution does not depend on de novo protein synthesis, and it is accompanied by a major increase in the probability that respiratory electrons are transferred to photosystem I rather than to a terminal oxidase. These results indicate that the distribution of complexes on the scale of 100-300 nm controls the partitioning of reducing power and that redistribution of electron transport complexes on these scales is a physiological mechanism to regulate the pathways of electron flow.
Collapse
|
24
|
Cyanobacterial metallochaperone inhibits deleterious side reactions of copper. Proc Natl Acad Sci U S A 2011; 109:95-100. [PMID: 22198771 DOI: 10.1073/pnas.1117515109] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Copper metallochaperones supply copper to cupro-proteins through copper-mediated protein-protein-interactions and it has been hypothesized that metallochaperones thereby inhibit copper from causing damage en route. Evidence is presented in support of this latter role for cyanobacterial metallochaperone, Atx1. In cyanobacteria Atx1 contributes towards the supply of copper to plastocyanin inside thylakoids but it is shown here that in copper-replete medium, copper can reach plastocyanin without Atx1. Unlike metallochaperone-independent copper-supply to superoxide dismutase in eukaryotes, glutathione is not essential for Atx1-independent supply to plastocyanin: Double mutants missing atx1 and gshB (encoding glutathione synthetase) accumulate the same number of atoms of copper per cell in the plastocyanin pool as wild type. Critically, Δatx1ΔgshB are hypersensitive to elevated copper relative to wild type cells and also relative to ΔgshB single mutants with evidence that hypersensitivity arises due to the mislocation of copper to sites for other metals including iron and zinc. The zinc site on the amino-terminal domain (ZiaA(N)) of the P(1)-type zinc-transporting ATPase is especially similar to the copper site of the Atx1 target PacS(N), and ZiaA(N) will bind Cu(I) more tightly than zinc. An NMR model of a substituted-ZiaA(N)-Cu(I)-Atx1 heterodimer has been generated making it possible to visualize a juxtaposition of residues surrounding the ZiaA(N) zinc site, including Asp(18), which normally repulse Atx1. Equivalent repulsion between bacterial copper metallochaperones and the amino-terminal regions of P(1)-type ATPases for metals other than Cu(I) is conserved, again consistent with a role for copper metallochaperones to withhold copper from binding sites for other metals.
Collapse
|
25
|
Li T, Yang HM, Cui SX, Suzuki I, Zhang LF, Li L, Bo TT, Wang J, Murata N, Huang F. Proteomic Study of the Impact of Hik33 Mutation in Synechocystis sp. PCC 6803 under Normal and Salt Stress Conditions. J Proteome Res 2011; 11:502-14. [DOI: 10.1021/pr200811s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tao Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao-Meng Yang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Su-Xia Cui
- College of Life Sciences, Capital Normal University, Beijing 100037, China
| | - Iwane Suzuki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan
| | - Li-Fang Zhang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Li Li
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting-Ting Bo
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Wang
- National Center of Biomedical Analysis, Beijing, China
| | - Norio Murata
- National Institute for Basic Biology, Okazaki 444-8585, Japan
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, P.O. Box 80203 Jeddah 21589, KSA
| | - Fang Huang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| |
Collapse
|
26
|
Barnett JP, Robinson C, Scanlan DJ, Blindauer CA. The Tat protein export pathway and its role in cyanobacterial metalloprotein biosynthesis. FEMS Microbiol Lett 2011; 325:1-9. [PMID: 22092855 DOI: 10.1111/j.1574-6968.2011.02391.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 08/11/2011] [Accepted: 08/16/2011] [Indexed: 11/27/2022] Open
Abstract
The Tat pathway is a common protein translocation system that is found in the bacterial cytoplasmic membrane, as well as in the cyanobacterial and plant thylakoid membranes. It is unusual in that the Tat pathway transports fully folded, often metal cofactor-containing proteins across these membranes. In bacteria, the Tat pathway plays an important role in the biosynthesis of noncytoplasmic metalloproteins. By compartmentalizing protein folding to the cytoplasm, the potentially aberrant binding of non-native metal ions to periplasmic proteins is avoided. To date, most of our understanding of Tat function has been obtained from studies using Escherichia coli as a model organism but cyanobacteria have an extra layer of complexity with proteins targeted to both the cytoplasmic and thylakoid membranes. We examine our current understanding of the Tat pathway in cyanobacteria and its role in metalloprotein biosynthesis.
Collapse
Affiliation(s)
- James P Barnett
- Department of Chemistry, University of Warwick, Coventry, UK.
| | | | | | | |
Collapse
|
27
|
Recombinant Deg/HtrA proteases from Synechocystis sp. PCC 6803 differ in substrate specificity, biochemical characteristics and mechanism. Biochem J 2011; 435:733-42. [PMID: 21332448 PMCID: PMC3195437 DOI: 10.1042/bj20102131] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Cyanobacteria require efficient protein-quality-control mechanisms to survive under dynamic, often stressful, environmental conditions. It was reported that three serine proteases, HtrA (high temperature requirement A), HhoA (HtrA homologue A) and HhoB (HtrA homologue B), are important for survival of Synechocystis sp. PCC 6803 under high light and temperature stresses and might have redundant physiological functions. In the present paper, we show that all three proteases can degrade unfolded model substrates, but differ with respect to cleavage sites, temperature and pH optima. For recombinant HhoA, and to a lesser extent for HtrA, we observed an interesting shift in the pH optimum from slightly acidic to alkaline in the presence of Mg2+ and Ca2+ ions. All three proteases formed different homo-oligomeric complexes with and without substrate, implying mechanistic differences in comparison with each other and with the well-studied Escherichia coli orthologues DegP (degradation of periplasmic proteins P) and DegS. Deletion of the PDZ domain decreased, but did not abolish, the proteolytic activity of all three proteases, and prevented substrate-induced formation of complexes higher than trimers by HtrA and HhoA. In summary, biochemical characterization of HtrA, HhoA and HhoB lays the foundation for a better understanding of their overlapping, but not completely redundant, stress-resistance functions in Synechocystis sp. PCC 6803.
Collapse
|
28
|
Chungjatupornchai W, Kamlangdee A, Fa-Aroonsawat S. Display of organophosphorus hydrolase on the cyanobacterial cell surface using synechococcus outer membrane protein a as an anchoring motif. Appl Biochem Biotechnol 2011; 164:1048-57. [PMID: 21327741 DOI: 10.1007/s12010-011-9193-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 01/31/2011] [Indexed: 11/24/2022]
Abstract
The display of proteins to cyanobacterial cell surface is made complex by combination of Gram-positive and Gram-negative features of cyanobacterial cell wall. Here, we showed that Synechococcus outer membrane protein A (SomA) can be used as an anchoring motif for the display of organophosphorus hydrolase (OPH) on cyanobacterial cell surface. The OPH, capable of degrading a wide range of organophosphate pesticides, was fused in frame to the carboxyl-terminus of different cell-surface exposed loops of SomA. Proteinase K accessibility assay and immunostaining visualized under confocal laser scanning microscopy demonstrated that a minor fraction of OPH with 12 histidines fused in frame with the third cell-surface exposed loop of SomA (SomAL3-OPH12H) was displayed onto the outermost cell surface with a substantial fraction buried in the cell wall, whereas OPH fused in frame with the fifth cell-surface exposed loop of SomA (SomAL5-OPH) was successfully translocated across the membrane and completely displayed onto the outermost surface of Synechococcus. The successful display of the functional heterologous protein on cell surface provides a useful model for variety of applications in cyanobacteria including screening of polypeptide libraries and whole-cell biocatalysts by immobilizing enzymes.
Collapse
Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand.
| | | | | |
Collapse
|
29
|
Zhang LF, Yang HM, Cui SX, Hu J, Wang J, Kuang TY, Norling B, Huang F. Proteomic analysis of plasma membranes of cyanobacterium Synechocystis sp. Strain PCC 6803 in response to high pH stress. J Proteome Res 2009; 8:2892-902. [PMID: 19351138 DOI: 10.1021/pr900024w] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacteria are unique prokaryotes possessing plasma-, outer- and thylakoid membranes. The plasma membrane of a cyanobacterial cell serves as a crucial barrier against its environment and is essential for biogenesis of cyanobacterial photosystems. Previously, we have identified 79 different proteins in the plasma membrane of Synechocystis sp. Strain PCC 6803 based on 2D- and 1D- gels and MALDI-TOF MS. In this work, we have performed a proteomic study screening for high-pH-stress proteins in Synechocystis. 2-D gel profiles of plasma membranes isolated from both control and high pH-treated cells were constructed and compared quantitatively based on different protein staining methods including DIGE analysis. A total of 55 differentially expressed protein spots were identified using MALDI-TOF MS and MALDI-TOF/TOF MS, corresponding to 39 gene products. Twenty-five proteins were enhanced/induced and 14 reduced by high pH. One-third of the enhanced/induced proteins were transport and binding proteins of ABC transporters including 3 phosphate transport proteins. Other proteins include MinD involved in cell division, Cya2 in signaling and proteins involved in photosynthesis and respiration. Furthermore, among these proteins regulated by high pH, eight were found to be hypothetical proteins. Functional significance of the high-pH-stress proteins is discussed integrating current knowledge on cyanobacterial cell physiology.
Collapse
Affiliation(s)
- Li-Fang Zhang
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Abstract
The cyanelles of the glaucocystophyte alga Cyanophora paradoxa resemble endosymbiotic cyanobacteria in morphology, pigmentation and, especially, in the presence of a peptidoglycan wall situated between the inner and outer envelope membranes. However, it is now clear that cyanelles in fact are primitive plastids. Phylogenetic analyses of plastid, nuclear and mitochondrial genes support a single primary endosymbiotic event. In this scenario cyanelles and all other plastid types are derived from an ancestral photosynthetic organelle combining the high plastid gene content of the Porphyra purpurea rhodoplast and the peptidoglycan wall of glaucocystophyte cyanelles. This means that the import apparatus of all primary plastids should be homologous. Indeed, heterologous in vitro import can now be shown in both directions, provided a phenylalanine residue essential for cyanelle import is engineered into the N-terminal part of chloroplast transit peptides. The cyanelle and likely also the rhodoplast import apparatus can be envisaged as prototypes with a single receptor showing this requirement for N-terminal phenylalanine. In chloroplasts, multiple receptors with overlapping and less stringent specificities have evolved explaining the efficient heterologous import of native precursors from C. paradoxa. With respect to conservative sorting in cyanelles, both the Sec and Tat pathways could be demonstrated. Another cyanobacterial feature, the dual location of the Sec translocase in thylakoid and inner envelope membranes, is also unique to cyanelles. For the first time, protease protection of internalized lumenal proteins could be shown for cyanobacteria-like, phycobilisome-bearing thylakoid membranes after import into isolated cyanelles.
Collapse
Affiliation(s)
- Jürgen M Steiner
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Biochemistry and Molecular Cell Biology, Dr. Bohrgasse 9, 1030 Vienna, Austria
| | | |
Collapse
|
31
|
Chungjatupornchai W, Fa-aroonsawat S. Translocation of green fluorescent protein to cyanobacterial periplasm using ice nucleation protein. J Microbiol 2009; 47:187-92. [PMID: 19412603 DOI: 10.1007/s12275-008-0188-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 12/07/2008] [Indexed: 10/20/2022]
Abstract
The translocation of proteins to cyanobacterial cell envelope is made complex by the presence of a highly differentiated membrane system. To investigate the protein translocation in cyanobacterium Synechococcus PCC 7942 using the truncated ice nucleation protein (InpNC) from Pseudomonas syringae KCTC 1832, the green fluorescent protein (GFP) was fused in frame to the carboxyl-terminus of InpNC. The fluorescence of GFP was found almost entirely as a halo in the outer regions of cells which appeared to correspond to the periplasm as demonstrated by confocal laser scanning microscopy, however, GFP was not displayed on the outermost cell surface. Western blotting analysis revealed that InpNC-GFP fusion protein was partially degraded. The N-terminal domain of InpNC may be susceptible to protease attack; the remaining C-terminal domain conjugated with GFP lost the ability to direct translocation across outer membrane and to act as a surface display motif. The fluorescence intensity of cells with periplasmic GFP was approximately 6-fold lower than that of cells with cytoplasmic GFP. The successful translocation of the active GFP to the periplasm may provide a potential means to study the property of cyanobacterial periplasmic substances in response to environmental changes in a non-invasive manner.
Collapse
Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakornpathom, 73170, Thailand.
| | | |
Collapse
|
32
|
Kaňa R, Prášil O, Mullineaux CW. Immobility of phycobilins in the thylakoid lumen of a cryptophyte suggests that protein diffusion in the lumen is very restricted. FEBS Lett 2009; 583:670-4. [DOI: 10.1016/j.febslet.2009.01.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 12/23/2008] [Accepted: 01/05/2009] [Indexed: 11/28/2022]
|
33
|
Yusa F, Steiner JM, Löffelhardt W. Evolutionary conservation of dual Sec translocases in the cyanelles of Cyanophora paradoxa. BMC Evol Biol 2008; 8:304. [PMID: 18976493 PMCID: PMC2600650 DOI: 10.1186/1471-2148-8-304] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 11/01/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cyanelles, the peptidoglycan-armored plastids of glaucocystophytes, occupy a unique bridge position in between free-living cyanobacteria and chloroplasts. In some respects they side with cyanobacteria whereas other features are clearly shared with chloroplasts. The Sec translocase, an example for "conservative sorting" in the course of evolution, is found in the plasma membrane of all prokaryotes, in the thylakoid membrane of chloroplasts and in both these membrane types of cyanobacteria. RESULTS In this paper we present evidence for a dual location of the Sec translocon in the thylakoid as well as inner envelope membranes of the cyanelles from Cyanophora paradoxa, i. e. conservative sorting sensu stricto. The prerequisite was the generation of specific antisera directed against cyanelle SecY that allowed immunodetection of the protein on SDS gels from both membrane types separated by sucrose density gradient floatation centrifugation. Immunoblotting of blue-native gels yielded positive but differential results for both the thylakoid and envelope Sec complexes, respectively. In addition, heterologous antisera directed against components of the Toc/Tic translocons and binding of a labeled precursor protein were used to discriminate between inner and outer envelope membranes. CONCLUSION The envelope translocase can be envisaged as a prokaryotic feature missing in higher plant chloroplasts but retained in cyanelles, likely for protein transport to the periplasm. Candidate passengers are cytochrome c6 and enzymes of peptidoglycan metabolism. The minimal set of subunits of the Toc/Tic translocase of a primitive plastid is proposed.
Collapse
Affiliation(s)
- Fumie Yusa
- SLT, Nagahama-city, Shiga-ken 526-0829, Japan.
| | | | | |
Collapse
|
34
|
Abstract
Protein diffusion in and around the photosynthetic membrane must play a crucial role in photosynthetic functions including electron transport, regulation of light-harvesting, and biogenesis, turnover and repair of membrane components. Protein mobility is controlled by a complex web of specific interactions, plus the viscosity of the environment and the extent of macromolecular crowding. I discuss the techniques that can be used to measure protein mobility in photosynthetic membranes. I then summarize what we know about the constraints on protein mobility imposed by macromolecular aggregation and crowding in and around the thylakoid membranes of green plants and cyanobacteria, with particular reference to the fluidity of the thylakoid membrane and the aqueous phases on either side of the membrane (the stroma/cytoplasm and the thylakoid lumen). Current indications are that the stroma/cytoplasm is a relatively fluid environment, whereas protein mobility in the lumen may be extremely restricted. The thylakoid membrane itself has an intermediate fluidity: some protein complexes are virtually immobile, probably due to their incorporation into large, stable macromolecular aggregates. However, there is sufficient free space to allow the long-range diffusion of some complexes. Finally, I discuss some future directions for research in this area.
Collapse
Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK.
| |
Collapse
|
35
|
Aldridge C, Spence E, Kirkilionis MA, Frigerio L, Robinson C. Tat-dependent targeting of Rieske iron-sulphur proteins to both the plasma and thylakoid membranes in the cyanobacterium Synechocystis PCC6803. Mol Microbiol 2008; 70:140-50. [PMID: 18699865 DOI: 10.1111/j.1365-2958.2008.06401.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cyanobacteria possess a differentiated membrane system and transport proteins into both the periplasm and thylakoid lumen. We have used green fluorescent protein (GFP)-tagged constructs to study the Tat protein transporter and Rieske Tat substrates in Synechocystis PCC6803. The Tat system has been shown to operate in the plasma membrane; we show here that it is also relatively abundant in the thylakoid membrane network, indicating that newly synthesized Tat substrates are targeted to both membrane systems. Synechocystis contains three Rieske iron-sulphur proteins, all of which contain typical twin-arginine signal-like sequences at their N-termini. We show that two of these proteins (PetC1 and PetC2) are obligate Tat substrates when expressed in Escherichia coli. The Rieske proteins exhibit differential localization in Synechocystis 6803; PetC1 and PetC2 are located in the thylakoid membrane, while PetC3 is primarily targeted to the plasma membrane. The combined data show that Tat substrates are directed with high precision to both membrane systems in this cyanobacterium, raising the question of how, and when, intracellular sorting to the correct membrane is achieved.
Collapse
Affiliation(s)
- Cassie Aldridge
- Department of Biological Sciences, University of Warwick, Coventry, UK
| | | | | | | | | |
Collapse
|
36
|
Mullineaux CW, Mariscal V, Nenninger A, Khanum H, Herrero A, Flores E, Adams DG. Mechanism of intercellular molecular exchange in heterocyst-forming cyanobacteria. EMBO J 2008; 27:1299-308. [PMID: 18388860 DOI: 10.1038/emboj.2008.66] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 03/04/2008] [Indexed: 11/09/2022] Open
Abstract
Heterocyst-forming filamentous cyanobacteria are true multicellular prokaryotes, in which heterocysts and vegetative cells have complementary metabolism and are mutually dependent. The mechanism for metabolite exchange between cells has remained unclear. To gain insight into the mechanism and kinetics of metabolite exchange, we introduced calcein, a 623-Da fluorophore, into the Anabaena cytoplasm. We used fluorescence recovery after photobleaching to quantify rapid diffusion of this molecule between the cytoplasms of all the cells in the filament. This indicates nonspecific intercellular channels allowing the movement of molecules from cytoplasm to cytoplasm. We quantify rates of molecular exchange as filaments adapt to diazotrophic growth. Exchange among vegetative cells becomes faster as filaments differentiate, becoming considerably faster than exchange with heterocysts. Slower exchange is probably a price paid to maintain a microaerobic environment in the heterocyst. We show that the slower exchange is partly due to the presence of cyanophycin polar nodules in heterocysts. The phenotype of a null mutant identifies FraG (SepJ), a membrane protein localised at the cell-cell interface, as a strong candidate for the channel-forming protein.
Collapse
Affiliation(s)
- Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK.
| | | | | | | | | | | | | |
Collapse
|
37
|
Mariscal V, Herrero A, Flores E. Continuous periplasm in a filamentous, heterocyst-forming cyanobacterium. Mol Microbiol 2007; 65:1139-45. [PMID: 17645442 DOI: 10.1111/j.1365-2958.2007.05856.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cyanobacteria bear a Gram-negative type of cell wall that includes a peptidoglycan layer and an outer membrane outside of the cytoplasmic membrane. In filamentous cyanobacteria, the outer membrane appears to be continuous along the filament of cells. In the heterocyst-forming cyanobacteria, two cell types contribute specialized functions for growth: vegetative cells provide reduced carbon to heterocysts, which provide N2-derived fixed nitrogen to vegetative cells. The promoter of the patS gene, which is active specifically in developing proheterocysts and heterocysts of Anabaena sp. PCC 7120, was used to direct the expression of altered versions of the gfp gene. An engineered green fluorescent protein (GFP) that was exported to the periplasm of the proheterocysts through the twin-arginine translocation system was observed also in the periphery of neighbouring vegetative cells. However, if the GFP was anchored to the cytoplasmic membrane, it was observed in the periphery of the producing proheterocysts or heterocysts but not in adjacent vegetative cells. These results show that there is no cytoplasmic membrane continuity between heterocysts and vegetative cells and that the GFP protein can move along the filament in the periplasm, which is functionally continuous and so provides a conduit that can be used for chemical communication between cells.
Collapse
Affiliation(s)
- Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C. and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain
| | | | | |
Collapse
|
38
|
Huesgen PF, Scholz P, Adamska I. The serine protease HhoA from Synechocystis sp. strain PCC 6803: substrate specificity and formation of a hexameric complex are regulated by the PDZ domain. J Bacteriol 2007; 189:6611-8. [PMID: 17616590 PMCID: PMC2045181 DOI: 10.1128/jb.00883-07] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enzymes of the ATP-independent Deg serine endopeptidase family are very flexible with regard to their substrate specificity. Some family members cleave only one substrate, while others act as general proteases on unfolded substrates. The proteolytic activity of Deg proteases is regulated by PDZ protein interaction domains. Here we characterized the HhoA protease from Synechocystis sp. strain PCC 6803 in vitro using several recombinant protein constructs. The proteolytic activity of HhoA was found to increase with temperature and basic pH and was stimulated by the addition of Mg(2+) or Ca(2+). We found that the single PDZ domain of HhoA played a critical role in regulating protease activity and in the assembly of a hexameric complex. Deletion of the PDZ domain strongly reduced proteolysis of a sterically challenging resorufin-labeled casein substrate, but unlabeled beta-casein was still degraded. Reconstitution of the purified HhoA with total membrane proteins isolated from Synechocystis sp. wild-type strain PCC 6803 and a DeltahhoA mutant resulted in specific degradation of selected proteins at elevated temperatures. We concluded that a single PDZ domain of HhoA plays a critical role in defining the protease activity and oligomerization state, combining the functions that are attributed to two PDZ domains in the homologous DegP protease from Escherichia coli. Based on this first enzymatic study of a Deg protease from cyanobacteria, we propose a general role for HhoA in the quality control of extracytoplasmic proteins, including membrane proteins, in Synechocystis sp. strain PCC 6803.
Collapse
Affiliation(s)
- Pitter F Huesgen
- Department of Physiology and Plant Biochemistry, University of Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
| | | | | |
Collapse
|
39
|
Rajalahti T, Huang F, Klement MR, Pisareva T, Edman M, Sjöström M, Wieslander A, Norling B. Proteins in different Synechocystis compartments have distinguishing N-terminal features: a combined proteomics and multivariate sequence analysis. J Proteome Res 2007; 6:2420-34. [PMID: 17508731 DOI: 10.1021/pr0605973] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyanobacteria have a cell envelope consisting of a plasma membrane, a periplasmic space with a peptidoglycan layer, and an outer membrane. A third, separate membrane system, the intracellular thylakoid membranes, is the site for both photosynthesis and respiration. All membranes and luminal spaces have unique protein compositions, which impose an intriguing mechanism for protein sorting of extracytoplasmic proteins due to single sets of translocation protein genes. It is shown here by multivariate sequence analyses of many experimentally identified proteins in Synechocystis, that proteins routed for the different extracytosolic compartments have correspondingly different physicochemical properties in their signal peptide and mature N-terminal segments. The full-length mature sequences contain less significant information. From these multivariate, N-terminal property-profile models for proteins with single experimental localization, proteins with ambiguous localization could, to a large extent, be predicted to a defined compartment. The sequence properties involve amino acids varying especially in volume and polarizability and at certain positions in the sequence segments, in a manner typical for the various compartment classes. Potential means of the cell to recognize the property features are discussed, involving the translocation channels and two Type I signal peptidases with different cellular localization, and charge features at their membrane interfaces.
Collapse
Affiliation(s)
- Tarja Rajalahti
- Department of Chemistry, University of Bergen, Bergen, Norway
| | | | | | | | | | | | | | | |
Collapse
|
40
|
|
41
|
Waldron KJ, Tottey S, Yanagisawa S, Dennison C, Robinson NJ. A periplasmic iron-binding protein contributes toward inward copper supply. J Biol Chem 2006; 282:3837-46. [PMID: 17148438 DOI: 10.1074/jbc.m609916200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Periplasmic substrate binding proteins are known for iron, zinc, manganese, nickel, and molybdenum but not copper. Synechocystis PCC 6803 requires copper for thylakoid-localized plastocyanin and cytochrome oxidase. Here we show that mutants deficient in a periplasmic substrate binding protein FutA2 have low cytochrome oxidase activity and produce cytochrome c6 when grown under copper conditions (150 nm) in which wild-type cells use plastocyanin rather than cytochrome c6. Anaerobic separation of extracts by two-dimensional native liquid chromatography followed by metal analysis and peptide mass-fingerprinting establish that accumulation of copper-plastocyanin is impaired, but iron-ferredoxin is unaffected in DeltafutA2 grown in 150 nm copper. However, recombinant FutA2 binds iron in preference to copper in vitro with an apparent Fe(III) affinity similar to that of its paralog FutA1, the principal substrate binding protein for iron import. FutA2 is also associated with iron and not copper in periplasm extracts, and this Fe(III)-protein complex is absent in DeltafutA2. There are differences in the soluble protein and small-molecule complexes of copper and iron, and the total amount of both elements increases in periplasm extracts of DeltafutA2 relative to wild type. Changes in periplasm protein and small-molecule complexes for other metals are also observed in DeltafutA2. It is proposed that FutA2 contributes to metal partitioning in the periplasm by sequestering Fe(III), which limits aberrant Fe(III) associations with vital binding sites for other metals, including copper.
Collapse
Affiliation(s)
- Kevin J Waldron
- Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, Newcastle NE4 2HH, United Kingdom
| | | | | | | | | |
Collapse
|
42
|
Kikuchi Y, Date M, Itaya H, Matsui K, Wu LF. Functional analysis of the twin-arginine translocation pathway in Corynebacterium glutamicum ATCC 13869. Appl Environ Microbiol 2006; 72:7183-92. [PMID: 16997984 PMCID: PMC1636197 DOI: 10.1128/aem.01528-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Compared to those of other gram-positive bacteria, the genetic structure of the Corynebacterium glutamicum Tat system is unique in that it contains the tatE gene in addition to tatA, tatB, and tatC. The tatE homologue has been detected only in the genomes of gram-negative enterobacteria. To assess the function of the C. glutamicum Tat pathway, we cloned the tatA, tatB, tatC, and tatE genes from C. glutamicum ATCC 13869 and constructed mutants carrying deletions of each tat gene or of both the tatA and tatE genes. Using green fluorescent protein (GFP) fused with the twin-arginine signal peptide of the Escherichia coli TorA protein, we demonstrated that the minimal functional Tat system required TatA and TatC. TatA and TatE provide overlapping function. Unlike the TatB proteins from gram-negative bacteria, C. glutamicum TatB was dispensable for Tat function, although it was required for maximal efficiency of secretion. The signal peptide sequence of the isomaltodextranase (IMD) of Arthrobacter globiformis contains a twin-arginine motif. We showed that both IMD and GFP fused with the signal peptide of IMD were secreted via the C. glutamicum Tat pathway. These observations indicate that IMD is a bona fide Tat substrate and imply great potential of the C. glutamicum Tat system for industrial production of heterologous folded proteins.
Collapse
Affiliation(s)
- Yoshimi Kikuchi
- Institute of Life Sciences, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan.
| | | | | | | | | |
Collapse
|
43
|
Liberton M, Howard Berg R, Heuser J, Roth R, Pakrasi HB. Ultrastructure of the membrane systems in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803. PROTOPLASMA 2006; 227:129-38. [PMID: 16736255 DOI: 10.1007/s00709-006-0145-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 07/05/2005] [Indexed: 05/09/2023]
Abstract
Among prokaryotes, cyanobacteria are unique in having highly differentiated internal membrane systems. Like other Gram-negative bacteria, cyanobacteria such as Synechocystis sp. strain PCC 6803 have a cell envelope consisting of a plasma membrane, peptidoglycan layer, and outer membrane. In addition, these organisms have an internal system of thylakoid membranes where the electron transfer reactions of photosynthesis and respiration occur. A long-standing controversy concerning the cellular ultrastructures of these organisms has been whether the thylakoid membranes exist inside the cell as separate compartments, or if they have physical continuity with the plasma membrane. Advances in cellular preservation protocols as well as in image acquisition and manipulation techniques have facilitated a new examination of this topic. We have used a combination of electron microscopy techniques, including freeze-etched as well as freeze-substituted preparations, in conjunction with computer-aided image processing to generate highly detailed images of the membrane systems in Synechocystis cells. We show that the thylakoid membranes are in fact physically discontinuous from the plasma membrane in this cyanobacterium. Thylakoid membranes in Synechocystis sp. strain PCC 6803 thus represent bona fide intracellular organelles, the first example of such compartments in prokaryotic cells.
Collapse
Affiliation(s)
- Michelle Liberton
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
| | | | | | | | | |
Collapse
|
44
|
Huang F, Fulda S, Hagemann M, Norling B. Proteomic screening of salt-stress-induced changes in plasma membranes of Synechocystis sp. strain PCC 6803. Proteomics 2006; 6:910-20. [PMID: 16400685 DOI: 10.1002/pmic.200500114] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The plasma membrane of a cyanobacterial cell is crucial as barrier against the outer medium. It is also an energy-transducing membrane as well as essential for biogenesis of cyanobacterial photosystems and the endo-membrane system. Previously we have identified 57 different proteins in the plasma membrane of control cells from Synechocystis sp. strain PCC6803. In the present work, proteomic screening of salt-stress proteins in the plasma membrane resulted in identification of 109 proteins corresponding to 66 different gene products. Differential and quantitative analyses of 2-DE profiles of plasma membranes isolated from both control and salt-acclimated cells revealed that twenty proteins were enhanced/induced and five reduced during salt stress. More than half of the enhanced/induced proteins were periplasmic binding proteins of ABC-transporters or hypothetical proteins. Proteins that exhibited the highest enhancement during salt stress include FutA1 (Slr1295) and Vipp1 (Sll0617), which have been suggested to be involved in protection of photosystem II under iron deficiency and in thylakoid membrane formation, respectively. Other salt-stress proteins were regulatory proteins such as PII protein, LrtA, and a protein that belongs to CheY subfamily. The physiological significance of the identified salt-stress proteins in the plasma membrane is discussed integrating our current knowledge on cyanobacterial stress physiology.
Collapse
Affiliation(s)
- Fang Huang
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Stockholm, Sweden
| | | | | | | |
Collapse
|
45
|
Srivastava R, Pisareva T, Norling B. Proteomic studies of the thylakoid membrane of Synechocystis sp. PCC 6803. Proteomics 2006; 5:4905-16. [PMID: 16287171 DOI: 10.1002/pmic.200500111] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Purified thylakoid membranes from the cyanobacterium Synechocystis sp. PCC 6803 were used for the first time in proteomic studies. The membranes were prepared by a combination of sucrose density centrifugation and aqueous polymer two-phase partitioning. In total, 76 different proteins were identified from 2- and 1-D gels by MALDI-TOF MS analysis. Twelve of the identified proteins have a predicted Sec/Tat signal peptide. Fourteen of the proteins were known, or predicted to be, integral membrane proteins. Among the proteins identified were subunits of the well-characterized thylakoid membrane constituents Photosystem I and II, ATP synthase, cytochrome b6f-complex, NADH dehydrogenase, and phycobilisome complex. In addition, novel thylakoid membrane proteins, both integral and peripheral were found, including enzymes involved in protein folding and pigment biosynthesis. The latter were the chlorophyll biosynthesis enzymes, light-dependent protochlorophyllide reductase and geranylgeranyl reductase as well as phytoene desaturase involved in carotenoid biosynthesis and a water-soluble carotenoid-binding protein. Interestingly, in view of the protein sorting mechanism in cyanobacteria, one of the two signal peptidases type I of Synechocystis was found in the thylakoid membrane, whereas the second one has been identified previously in the plasma membrane. Sixteen proteins are hypothetical proteins with unknown function.
Collapse
Affiliation(s)
- Renu Srivastava
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-10691 Stockholm, Sweden
| | | | | |
Collapse
|
46
|
Komenda J, Barker M, Kuviková S, de Vries R, Mullineaux CW, Tichy M, Nixon PJ. The FtsH protease slr0228 is important for quality control of photosystem II in the thylakoid membrane of Synechocystis sp. PCC 6803. J Biol Chem 2005; 281:1145-51. [PMID: 16286465 DOI: 10.1074/jbc.m503852200] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyanobacterium Synechocystis sp. PCC 6803 contains four members of the FtsH protease family. One of these, FtsH (slr0228), has been implicated recently in the repair of photodamaged photosystem II (PSII) complexes. We have demonstrated here, using a combination of blue native PAGE, radiolabeling, and immunoblotting, that FtsH (slr0228) is required for selective replacement of the D1 reaction center subunit in both wild type PSII complexes and in PSII subcomplexes lacking the PSII chlorophyll a-binding subunit CP43. To test whether FtsH (slr0228) has a more general role in protein quality control in vivo, we have studied the synthesis and degradation of PSII subunits in wild type and in defined insertion and missense mutants incapable of proper assembly of the PSII holoenzyme. We discovered that, when the gene encoding FtsH (slr0228) was disrupted in these strains, the overall level of assembly intermediates and unassembled PSII proteins markedly increased. Pulse-chase experiments showed that this was due to reduced rates of degradation in vivo. Importantly, analysis of epitope-tagged and green fluorescent protein-tagged strains revealed that slr0228 was present in the thylakoid and not the cytoplasmic membrane. Overall, our results show that FtsH (slr0228) plays an important role in controlling the removal of PSII subunits from the thylakoid membrane and is not restricted to selective D1 turnover.
Collapse
Affiliation(s)
- Josef Komenda
- Institute of Microbiology, Academy of Sciences, Opatovický mlýn, Trebon, Czech Republic.
| | | | | | | | | | | | | |
Collapse
|
47
|
Joshua S, Mullineaux CW. The rpaC gene product regulates phycobilisome-photosystem II interaction in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1709:58-68. [PMID: 16023072 DOI: 10.1016/j.bbabio.2005.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Revised: 06/01/2005] [Accepted: 06/19/2005] [Indexed: 11/23/2022]
Abstract
State transitions in cyanobacteria are a physiological adaptation mechanism that changes the interaction of the phycobilisomes with the Photosystem I and Photosystem II core complexes. A random mutagenesis study in the cyanobacterium Synechocystis sp. PCC6803 identified a gene named rpaC which appeared to be specifically required for state transitions. rpaC is a conserved cyanobacterial gene which was tentatively suggested to code for a novel signal transduction factor. The predicted gene product is a 9-kDa integral membrane protein. We have further examined the role of rpaC by overexpressing the gene in Synechocystis 6803 and by inactivating the ortholog in a second cyanobacterium, Synechococcus sp. PCC7942. Unlike the Synechocystis 6803 null mutant, the Synechococcus 7942 null mutant is unable to segregate, indicating that the gene is essential for cell viability in this cyanobacterium. The Synechocystis 6803 overexpressor is also unable to segregate, indicating that the cells can only tolerate a limited gene copy number. The non-segregated Synechococcus 7942 mutant can perform state transitions but shows a perturbed phycobilisome-Photosystem II interaction. Based on these results, we propose that the rpaC gene product controls the stability of the phycobilisome-Photosystem II supercomplex, and is probably a structural component of the complex.
Collapse
Affiliation(s)
- Sarah Joshua
- Department of Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | | |
Collapse
|
48
|
Tinker JK, Erbe JL, Holmes RK. Characterization of fluorescent chimeras of cholera toxin and Escherichia coli heat-labile enterotoxins produced by use of the twin arginine translocation system. Infect Immun 2005; 73:3627-35. [PMID: 15908392 PMCID: PMC1111858 DOI: 10.1128/iai.73.6.3627-3635.2005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholera toxin (CT) is an AB(5) toxin responsible for the profuse secretory diarrhea resulting from Vibrio cholerae infection. CT consists of a pentameric, receptor-binding B subunit (CTB) and a monomeric A subunit (CTA) that has latent enzymatic activity. In addition to its enterotoxicity, CT has potent mucosal adjuvant activity and can also function as a carrier molecule with many potential applications in cell biology. In earlier studies, the toxic CTA(1) domain was replaced by several other antigenic protein domains to produce holotoxin-like chimeras for use as potential mucosal vaccines. In the present study we utilized the twin arginine translocation (tat) system to produce fluorescent CT chimeras, as well as fluorescent chimeras of Escherichia coli heat-labile toxins LTI and LTIIb. Fusion proteins containing either green fluorescent protein (GFP) or monomeric red fluorescent protein (mRFP) and the A(2) domain of CT, LTI, or LTIIb were transported to the periplasm of E. coli by the tat system, and the corresponding B polypeptides of CT, LTI, and LTIIb were transported to the periplasm by the sec system. The fluorescent fusion proteins were shown to assemble spontaneously and efficiently with the corresponding B polypeptides in the periplasm to form chimeric holotoxin-like molecules, and these chimeras bound to and entered cultured cells in a manner similar to native CT, LTI, or LTIIb. The GFP and mRFP derivatives of CT, LT, and LTIIb developed here are useful tools for studies on the cell biology of trafficking of the CT/LT family of bacterial enterotoxins. In addition, these constructs provide proof in principle for the development of novel chimeric CT-like or LT-like vaccine candidates containing CTA(2) fusion proteins that cannot be delivered to the periplasm of E. coli by use of the sec secretion pathway.
Collapse
Affiliation(s)
- Juliette K Tinker
- Department of Microbiology, Mail stop 8333, University of Colorado Health Sciences Center at Fitzsimmons, P.O. Box 6511, Aurora, CO 80045, USA
| | | | | |
Collapse
|
49
|
Steiner JM, Berghöfer J, Yusa F, Pompe JA, Klösgen RB, Löffelhardt W. Conservative sorting in a primitive plastid. The cyanelle of Cyanophora paradoxa. FEBS J 2005; 272:987-98. [PMID: 15691332 DOI: 10.1111/j.1742-4658.2004.04533.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Higher plant chloroplasts possess at least four different pathways for protein translocation across and protein integration into the thylakoid membranes. It is of interest with respect to plastid evolution, which pathways have been retained as a relic from the cyanobacterial ancestor ('conservative sorting'), which ones have been kept but modified, and which ones were developed at the organelle stage, i.e. are eukaryotic achievements as (largely) the Toc and Tic translocons for envelope import of cytosolic precursor proteins. In the absence of data on cyanobacterial protein translocation, the cyanelles of the glaucocystophyte alga Cyanophora paradoxa for which in vitro systems for protein import and intraorganellar sorting were elaborated can serve as a model: the cyanelles are surrounded by a peptidoglycan wall, their thylakoids are covered with phycobilisomes and the composition of their oxygen-evolving complex is another feature shared with cyanobacteria. We demonstrate the operation of the Sec and Tat pathways in cyanelles and show for the first time in vitro protein import across cyanobacteria-like thylakoid membranes and protease protection of the mature protein.
Collapse
Affiliation(s)
- Juergen M Steiner
- Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Biochemistry and Molecular Cell Biology and Ludwig Boltzmann Research Unit for Biochemistry, Vienna, Austria
| | | | | | | | | | | |
Collapse
|
50
|
Nassoury N, Morse D. Protein targeting to the chloroplasts of photosynthetic eukaryotes: getting there is half the fun. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1743:5-19. [PMID: 15777835 DOI: 10.1016/j.bbamcr.2004.09.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 08/10/2004] [Accepted: 09/17/2004] [Indexed: 11/19/2022]
Abstract
The plastids of many algae are surrounded by three or four membranes, thought to be a consequence of their evolutionary origin through secondary endosymbiosis between photosynthetic and non-photosynthetic eukaryotes. Each membrane constitutes a barrier to the passage of proteins, so protein targeting in these complex plastids has an extra level of difficulty when compared to higher plants. In the latter, protein translocation across the two membranes uses multi-protein complexes that together import proteins possessing an N-terminal leader sequence rich in serine and threonine (S/T). In contrast, while targeting to most complex plastids also involves an S/T-rich region, this region is preceded by an N-terminal hydrophobic signal peptide. This arrangement of peptide sequences suggests that proteins directed to complex plastids pass through the ER, as do other proteins with hydrophobic signal peptides. However, this simplistic view is not always easy to reconcile with what is known about the different secondary plastids. In the first group, with plastids bounded by three membranes, plastid-directed proteins do indeed arrive in Golgi-derived vesicles, but a second hydrophobic region follows the S/T-rich region in all leaders. In the second group, where four membranes completely surround the plastids, it is still not known how the proteins arrive at the plastids, and in addition, one member of this group uses a targeting signal rich in asparagine and lysine in place of the S/T-rich region. In the third group, the fourth bounding membrane is contiguous with the ER, but it is not clear what distinguishes plastid membranes from others in the endomembrane system. Knowing what to expect is important, as genomic sequencing programs may soon be turning up some of the missing pieces in these translocation puzzles.
Collapse
Affiliation(s)
- Nasha Nassoury
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke est, Montreal, Quebec, Canada H1X 2B2
| | | |
Collapse
|