151
|
Marques MC, Coelho R, De Lacey AL, Pereira IA, Matias PM. The Three-Dimensional Structure of [NiFeSe] Hydrogenase from Desulfovibrio vulgaris Hildenborough: A Hydrogenase without a Bridging Ligand in the Active Site in Its Oxidised, “as-Isolated” State. J Mol Biol 2010; 396:893-907. [DOI: 10.1016/j.jmb.2009.12.013] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 12/03/2009] [Accepted: 12/10/2009] [Indexed: 10/20/2022]
|
152
|
Grzyb J, Xu F, Weiner L, Reijerse EJ, Lubitz W, Nanda V, Noy D. De novo design of a non-natural fold for an iron–sulfur protein: Alpha-helical coiled-coil with a four-iron four-sulfur cluster binding site in its central core. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:406-13. [DOI: 10.1016/j.bbabio.2009.12.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 12/11/2009] [Accepted: 12/16/2009] [Indexed: 01/09/2023]
|
153
|
Agapakis CM, Ducat DC, Boyle PM, Wintermute EH, Way JC, Silver PA. Insulation of a synthetic hydrogen metabolism circuit in bacteria. J Biol Eng 2010; 4:3. [PMID: 20184755 PMCID: PMC2847965 DOI: 10.1186/1754-1611-4-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 02/25/2010] [Indexed: 02/04/2023] Open
Abstract
Background The engineering of metabolism holds tremendous promise for the production of desirable metabolites, particularly alternative fuels and other highly reduced molecules. Engineering approaches must redirect the transfer of chemical reducing equivalents, preventing these electrons from being lost to general cellular metabolism. This is especially the case for high energy electrons stored in iron-sulfur clusters within proteins, which are readily transferred when two such clusters are brought in close proximity. Iron sulfur proteins therefore require mechanisms to ensure interaction between proper partners, analogous to many signal transduction proteins. While there has been progress in the isolation of engineered metabolic pathways in recent years, the design of insulated electron metabolism circuits in vivo has not been pursued. Results Here we show that a synthetic hydrogen-producing electron transfer circuit in Escherichia coli can be insulated from existing cellular metabolism via multiple approaches, in many cases improving the function of the pathway. Our circuit is composed of heterologously expressed [Fe-Fe]-hydrogenase, ferredoxin, and pyruvate-ferredoxin oxidoreductase (PFOR), allowing the production of hydrogen gas to be coupled to the breakdown of glucose. We show that this synthetic pathway can be insulated through the deletion of competing reactions, rational engineering of protein interaction surfaces, direct protein fusion of interacting partners, and co-localization of pathway components on heterologous protein scaffolds. Conclusions Through the construction and characterization of a synthetic metabolic circuit in vivo, we demonstrate a novel system that allows for predictable engineering of an insulated electron transfer pathway. The development of this system demonstrates working principles for the optimization of engineered pathways for alternative energy production, as well as for understanding how electron transfer between proteins is controlled.
Collapse
|
154
|
Requirements for construction of a functional hybrid complex of photosystem I and [NiFe]-hydrogenase. Appl Environ Microbiol 2010; 76:2641-51. [PMID: 20154103 DOI: 10.1128/aem.02700-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The development of cellular systems in which the enzyme hydrogenase is efficiently coupled to the oxygenic photosynthesis apparatus represents an attractive avenue to produce H(2) sustainably from light and water. Here we describe the molecular design of the individual components required for the direct coupling of the O(2)-tolerant membrane-bound hydrogenase (MBH) from Ralstonia eutropha H16 to the acceptor site of photosystem I (PS I) from Synechocystis sp. PCC 6803. By genetic engineering, the peripheral subunit PsaE of PS I was fused to the MBH, and the resulting hybrid protein was purified from R. eutropha to apparent homogeneity via two independent affinity chromatographical steps. The catalytically active MBH-PsaE (MBH(PsaE)) hybrid protein could be isolated only from the cytoplasmic fraction. This was surprising, since the MBH is a substrate of the twin-arginine translocation system and was expected to reside in the periplasm. We conclude that the attachment of the additional PsaE domain to the small, electron-transferring subunit of the MBH completely abolished the export competence of the protein. Activity measurements revealed that the H(2) production capacity of the purified MBH(PsaE) fusion protein was very similar to that of wild-type MBH. In order to analyze the specific interaction of MBH(PsaE) with PS I, His-tagged PS I lacking the PsaE subunit was purified via Ni-nitrilotriacetic acid affinity and subsequent hydrophobic interaction chromatography. Formation of PS I-hydrogenase supercomplexes was demonstrated by blue native gel electrophoresis. The results indicate a vital prerequisite for the quantitative analysis of the MBH(PsaE)-PS I complex formation and its light-driven H(2) production capacity by means of spectroelectrochemistry.
Collapse
|
155
|
Goldet G, Brandmayr C, Stripp ST, Happe T, Cavazza C, Fontecilla-Camps JC, Armstrong FA. Electrochemical kinetic investigations of the reactions of [FeFe]-hydrogenases with carbon monoxide and oxygen: comparing the importance of gas tunnels and active-site electronic/redox effects. J Am Chem Soc 2010; 131:14979-89. [PMID: 19824734 DOI: 10.1021/ja905388j] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A major obstacle for future biohydrogen production is the oxygen sensitivity of [FeFe]-hydrogenases, the highly active catalysts produced by bacteria and green algae. The reactions of three representative [FeFe]-hydrogenases with O(2) have been studied by protein film electrochemistry under conditions of both H(2) oxidation and H(2) production, using CO as a complementary probe. The hydrogenases are DdHydAB and CaHydA from the bacteria Desulfovibrio desulfuricans and Clostridium acetobutylicum , and CrHydA1 from the green alga Chlamydomonas reinhardtii . Rates of inactivation depend on the redox state of the active site 'H-cluster' and on transport through the protein to reach the pocket in which the H-cluster is housed. In all cases CO reacts much faster than O(2). In the model proposed, CaHydA shows the most sluggish gas transport and hence little dependence of inactivation rate on H-cluster state, whereas DdHydAB shows a large dependence on H-cluster state and the least effective barrier to gas transport. All three enzymes show a similar rate of reactivation from CO inhibition, which increases upon illumination: the rate-determining step is thus assigned to cleavage of the labile Fe-CO bond, a reaction likely to be intrinsic to the atomic and electronic state of the H-cluster and less sensitive to the surrounding protein.
Collapse
Affiliation(s)
- Gabrielle Goldet
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
156
|
Iwuchukwu IJ, Vaughn M, Myers N, O'Neill H, Frymier P, Bruce BD. Self-organized photosynthetic nanoparticle for cell-free hydrogen production. NATURE NANOTECHNOLOGY 2010; 5:73-9. [PMID: 19898496 DOI: 10.1038/nnano.2009.315] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 09/26/2009] [Indexed: 05/05/2023]
Abstract
There is considerable interest in making use of solar energy through photosynthesis to create alternative forms of fuel. Here, we show that photosystem I from a thermophilic bacterium and cytochrome-c(6) can, in combination with a platinum catalyst, generate a stable supply of hydrogen in vitro upon illumination. The self-organized platinization of the photosystem I nanoparticles allows electron transport from sodium ascorbate to photosystem I via cytochrome-c(6) and finally to the platinum catalyst, where hydrogen gas is formed. Our system produces hydrogen at temperatures up to 55 degrees C and is temporally stable for >85 days with no decrease in hydrogen yield when tested intermittently. The maximum yield is approximately 5.5 micromol H(2) h(-1) mg(-1) chlorophyll and is estimated to be approximately 25-fold greater than current biomass-to-fuel strategies. Future work will further improve this yield by increasing the kinetics of electron transfer, extending the spectral response and replacing the platinum catalyst with a renewable hydrogenase.
Collapse
Affiliation(s)
- Ifeyinwa J Iwuchukwu
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | | | | | | | | |
Collapse
|
157
|
Reisner E, Powell DJ, Cavazza C, Fontecilla-Camps JC, Armstrong FA. Visible Light-Driven H2 Production by Hydrogenases Attached to Dye-Sensitized TiO2 Nanoparticles. J Am Chem Soc 2009; 131:18457-66. [DOI: 10.1021/ja907923r] [Citation(s) in RCA: 362] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Erwin Reisner
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom, and Laboratoire de Crystallographie et Crystallogènese des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horrowitz, 38027 Grenoble Cedex 1, France
| | - Daniel J. Powell
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom, and Laboratoire de Crystallographie et Crystallogènese des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horrowitz, 38027 Grenoble Cedex 1, France
| | - Christine Cavazza
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom, and Laboratoire de Crystallographie et Crystallogènese des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horrowitz, 38027 Grenoble Cedex 1, France
| | - Juan C. Fontecilla-Camps
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom, and Laboratoire de Crystallographie et Crystallogènese des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horrowitz, 38027 Grenoble Cedex 1, France
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom, and Laboratoire de Crystallographie et Crystallogènese des Protéines, Institut de Biologie Structurale, J.P. Ebel, CEA, CNRS, Université Joseph Fourier, 41, rue J. Horrowitz, 38027 Grenoble Cedex 1, France
| |
Collapse
|
158
|
Armstrong FA. Dynamic electrochemical experiments on hydrogenases. PHOTOSYNTHESIS RESEARCH 2009; 102:541-550. [PMID: 19455401 DOI: 10.1007/s11120-009-9428-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 04/23/2009] [Indexed: 05/27/2023]
Abstract
A powerful approach for studying hydrogenases, applying a suite of dynamic electrochemical techniques known as protein film electrochemistry, is trailblazing fresh discoveries and providing a wealth of quantitative data on these complex enzymes. The information now stemming from experiments on tiny quantities of hydrogenases ranges from their kinetics and catalytic bias (a preference to operate in H(2) oxidation vs. H(2) production) to wide differences in the ways they react with oxygen and other inhibitors. Tolerance of hydrogenase catalysis to oxygen is essential if organisms are to be exploited for photosynthetic hydrogen production, and is crucial in enabling aerobes to use trace H(2) as an energy source. Experiments described in this article may be adapted for other complex enzymes.
Collapse
Affiliation(s)
- Fraser A Armstrong
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, Oxford OX1 3QR, UK.
| |
Collapse
|
159
|
Long H, King PW, Ghirardi ML, Kim K. Hydrogenase/Ferredoxin Charge-Transfer Complexes: Effect of Hydrogenase Mutations on the Complex Association. J Phys Chem A 2009; 113:4060-7. [DOI: 10.1021/jp810409z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hai Long
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401
| | - Paul W. King
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401
| | - Maria L. Ghirardi
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401
| | - Kwiseon Kim
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, Colorado 80401
| |
Collapse
|
160
|
Summerfield TC, Toepel J, Sherman LA. Low-oxygen induction of normally cryptic psbA genes in cyanobacteria. Biochemistry 2009; 47:12939-41. [PMID: 18998707 DOI: 10.1021/bi8018916] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microarray analysis indicated low-O(2) conditions resulted in upregulation of psbA1, the normally low-abundance transcript that encodes the D1' protein of photosystem II in Synechocystis sp. PCC 6803. Using a DeltapsbA2:DeltapsbA3 strain, we show the psbA1 transcript is translated and the resultant D1' is inserted into functional PSII complexes. Two other cyanobacterial strains have psbA genes that were induced by low oxygen. In two of the three strains examined, psbA was part of an upregulated gene cluster including an alternative Rieske iron-sulfur protein. We conclude this cluster may represent an important adaptation to changing O(2) levels that cyanobacteria experience.
Collapse
Affiliation(s)
- Tina C Summerfield
- Department of Biological Sciences, Purdue University, 201 South University Street, Hansen Hall, West Lafayette, Indiana 47907, USA
| | | | | |
Collapse
|
161
|
Dubini A, Mus F, Seibert M, Grossman AR, Posewitz MC. Flexibility in anaerobic metabolism as revealed in a mutant of Chlamydomonas reinhardtii lacking hydrogenase activity. J Biol Chem 2009; 284:7201-13. [PMID: 19117946 PMCID: PMC2652310 DOI: 10.1074/jbc.m803917200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 12/29/2008] [Indexed: 11/06/2022] Open
Abstract
The green alga Chlamydomonas reinhardtii has a network of fermentation pathways that become active when cells acclimate to anoxia. Hydrogenase activity is an important component of this metabolism, and we have compared metabolic and regulatory responses that accompany anaerobiosis in wild-type C. reinhardtii cells and a null mutant strain for the HYDEF gene (hydEF-1 mutant), which encodes an [FeFe] hydrogenase maturation protein. This mutant has no hydrogenase activity and exhibits elevated accumulation of succinate and diminished production of CO2 relative to the parental strain during dark, anaerobic metabolism. In the absence of hydrogenase activity, increased succinate accumulation suggests that the cells activate alternative pathways for pyruvate metabolism, which contribute to NAD(P)H reoxidation, and continued glycolysis and fermentation in the absence of O2. Fermentative succinate production potentially proceeds via the formation of malate, and increases in the abundance of mRNAs encoding two malate-forming enzymes, pyruvate carboxylase and malic enzyme, are observed in the mutant relative to the parental strain following transfer of cells from oxic to anoxic conditions. Although C. reinhardtii has a single gene encoding pyruvate carboxylase, it has six genes encoding putative malic enzymes. Only one of the malic enzyme genes, MME4, shows a dramatic increase in expression (mRNA abundance) in the hydEF-1 mutant during anaerobiosis. Furthermore, there are marked increases in transcripts encoding fumarase and fumarate reductase, enzymes putatively required to convert malate to succinate. These results illustrate the marked metabolic flexibility of C. reinhardtii and contribute to the development of an informed model of anaerobic metabolism in this and potentially other algae.
Collapse
Affiliation(s)
- Alexandra Dubini
- Environmental Science and Engineering Division, Colorado School of Mines, Golden, Colorado 80401, USA
| | | | | | | | | |
Collapse
|
162
|
Bernát G, Waschewski N, Rögner M. Towards efficient hydrogen production: the impact of antenna size and external factors on electron transport dynamics in Synechocystis PCC 6803. PHOTOSYNTHESIS RESEARCH 2009; 99:205-16. [PMID: 19137411 DOI: 10.1007/s11120-008-9398-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 12/23/2008] [Indexed: 05/12/2023]
Abstract
Three Synechocystis PCC 6803 strains with different levels of phycobilisome antenna-deficiency have been investigated for their impact on photosynthetic electron transport and response to environmental factors (i.e. light-quality, -quantity and composition of growth media). Oxygen yield and P(700) reduction kinetic measurements showed enhanced linear electron transport rates-especially under photoautotrophic conditions-with impaired antenna-size, starting from wild type (WT) (full antenna) over DeltaapcE- (phycobilisomes functionally dissociated) and Olive (lacking phycocyanin) up to the PAL mutant (lacking the whole phycobilisome). In contrast to mixotrophic conditions (up to 80% contribution), cyclic electron transport plays only a minor role (below 10%) under photoautotrophic conditions for all the strains, while linear electron transport increased up to 5.5-fold from WT to PAL mutant. The minor contribution of the cyclic electron transport was proportionally increased with the linear one in the DeltaapcE and Olive mutant, but was not altered in the PAL mutant, indicating that upregulation of the linear route does not have to be correlated with downregulation of the cyclic electron transport. Antenna-deficiency involves higher linear electron transport rates by tuning the PS2/PS1 ratio from 1:5 in WT up to 1:1 in the PAL mutant. While state transitions were observed only in the WT and Olive mutant, a further ~30% increase in the PS2/PS1 ratio was achieved in all the strains by long-term adaptation to far red light (720 nm). These results are discussed in the context of using these cells for future H(2) production in direct combination with the photosynthetic electron transport and suggest both Olive and PAL as potential candidates for future manipulations toward this goal. In conclusion, the highest rates can be expected if mutants deficient in phycobilisome antennas are grown under photoautotrophic conditions in combination with uncoupling of electron transport and an illumination which excites preferably PS1.
Collapse
Affiliation(s)
- Gábor Bernát
- Lehrstuhl für Biochemie der Pflanzen, Ruhr Universität Bochum, 44780, Bochum, Germany.
| | | | | |
Collapse
|
163
|
English CM, Eckert C, Brown K, Seibert M, King PW. Recombinant and in vitro expression systems for hydrogenases: new frontiers in basic and applied studies for biological and synthetic H2 production. Dalton Trans 2009:9970-8. [DOI: 10.1039/b913426n] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
164
|
Hambourger M, Kodis G, Vaughn MD, Moore GF, Gust D, Moore AL, Moore TA. Solar energy conversion in a photoelectrochemical biofuel cell. Dalton Trans 2009:9979-89. [DOI: 10.1039/b912170f] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
165
|
Ghirardi ML, Dubini A, Yu J, Maness PC. Photobiological hydrogen-producing systems. Chem Soc Rev 2009; 38:52-61. [DOI: 10.1039/b718939g] [Citation(s) in RCA: 242] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
166
|
Allakhverdiev SI, Kreslavski VD, Thavasi V, Zharmukhamedov SK, Klimov VV, Nagata T, Nishihara H, Ramakrishna S. Hydrogen photoproduction by use of photosynthetic organisms and biomimetic systems. Photochem Photobiol Sci 2008; 8:148-56. [PMID: 19247505 DOI: 10.1039/b814932a] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen can be important clean fuel for future. Among different technologies for hydrogen production, oxygenic natural and artificial photosyntheses using direct photochemistry in synthetic complexes have a great potential to produce hydrogen, since both use clean and cheap sources: water and solar energy. Artificial photosynthesis is one way to produce hydrogen from water using sunlight by employing biomimetic complexes. However, splitting of water into protons and oxygen is energetically demanding and chemically difficult. In oxygenic photosynthetic microorganisms such as algae and cyanobacteria, water is split into electrons and protons, which during primary photosynthetic process are redirected by photosynthetic electron transport chain, and ferredoxin, to the hydrogen-producing enzymes hydrogenase or nitrogenase. By these enzymes, e- and H+ recombine and form gaseous hydrogen. Biohydrogen activity of hydrogenase can be very high but it is extremely sensitive to photosynthetic O2. In contrast, nitrogenase is insensitive to O2, but has lower activity. At the moment, the efficiency of biohydrogen production is low. However, theoretical expectations suggest that the rates of photon conversion efficiency for H2 bioproduction can be high enough (>10%). Our review examines the main pathways of H2 photoproduction by using of photosynthetic organisms and biomimetic photosynthetic systems.
Collapse
Affiliation(s)
- Suleyman I Allakhverdiev
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
| | | | | | | | | | | | | | | |
Collapse
|
167
|
Eberly JO, Ely RL. Thermotolerant hydrogenases: biological diversity, properties, and biotechnological applications. Crit Rev Microbiol 2008; 34:117-30. [PMID: 18728989 DOI: 10.1080/10408410802240893] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Hydrogenases are metalloproteins that catalyze the oxidation and reduction of molecular hydrogen and play a crucial role in many microbial metabolic processes. A subset of hydrogenases capable of functioning at temperatures from 50 to 125 degrees C is found in thermophilic microorganisms. Most known thermotolerant hydrogenases contain a [NiFe] active site and are either bidirectional or uptake type. Although no exhaustive survey has been done of the ecological diversity of thermophilic hydrogen-reducing or oxidizing bacteria, they appear to exist in virtually every thermophilic environment examined to date. Thermotolerant hydrogenases share many similarities with their mesophilic counterparts, but they have several features in addition to thermotolerance that make them especially well suited for biotechnological applications. Ongoing research is focused on potential applications of thermotolerant H2 ases in biosynthesis, H2 production, bioremediation, and biosensors.
Collapse
Affiliation(s)
- Jed O Eberly
- Department of Biological & Ecological Engineering, Oregon State University, Corvallis, Oregon 97331, USA
| | | |
Collapse
|
168
|
Armstrong FA, Belsey NA, Cracknell JA, Goldet G, Parkin A, Reisner E, Vincent KA, Wait AF. Dynamic electrochemical investigations of hydrogen oxidation and production by enzymes and implications for future technology. Chem Soc Rev 2008; 38:36-51. [PMID: 19088963 DOI: 10.1039/b801144n] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This tutorial review describes studies of hydrogen production and oxidation by biological catalysts--metalloenzymes known as hydrogenases--attached to electrodes. It explains how the electrocatalytic properties of hydrogenases are studied using specialised electrochemical techniques and how the data are interpreted to allow assessments of catalytic rates and performance under different conditions, including the presence of O2, CO and H2S. It concludes by drawing some comparisons between the enzyme active sites and platinum catalysts and describing some novel proof-of-concept applications that demonstrate the high activities and selectivities of these 'alternative' catalysts for promoting H2 as a fuel.
Collapse
Affiliation(s)
- Fraser A Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, UK OX1 3QR.
| | | | | | | | | | | | | | | |
Collapse
|
169
|
Chou CJ, Jenney FE, Adams MW, Kelly RM. Hydrogenesis in hyperthermophilic microorganisms: Implications for biofuels. Metab Eng 2008; 10:394-404. [DOI: 10.1016/j.ymben.2008.06.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 06/20/2008] [Indexed: 11/25/2022]
|
170
|
Curatti L, Giarrocco LE, Cumino AC, Salerno GL. Sucrose synthase is involved in the conversion of sucrose to polysaccharides in filamentous nitrogen-fixing cyanobacteria. PLANTA 2008; 228:617-625. [PMID: 18560883 DOI: 10.1007/s00425-008-0764-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 05/31/2008] [Indexed: 05/26/2023]
Abstract
Higher plants and cyanobacteria metabolize sucrose (Suc) by a similar set of enzymes. Suc synthase (SuS, UDP-glucose: D: -fructose 2-alpha-D: -glucosyl transferase, EC 2.4.1.13) catalyses the synthesis and cleavage of Suc, and in higher plants, it plays an important role in polysaccharides biosynthesis and carbon allocation. In this work, we have studied the functional relationship between SuS and the metabolism of polysaccharides in filamentous nitrogen-fixing cyanobacteria. We show that the nitrogen and carbon sources and light regulate the expression of the SuS encoding gene (susA), in a similar way that they regulate the accumulation of polysaccharides. Furthermore, glycogen content in an Anabaena sp. mutant strain with an insertion inactivation of susA was lower than in the wild type strain under diazotrophic conditions, while both glycogen and polysaccharides levels were higher in a mutant strain constitutively overexpressing susA. We also show that there are soluble and membrane-bound forms of SuS in Anabaena. Taken together, these results strongly suggest that SuS is involved in the Suc to polysaccharides conversion according to nutritional and environmental signals in filamentous nitrogen-fixing cyanobacteria.
Collapse
Affiliation(s)
- Leonardo Curatti
- Centro de Investigaciones Biológicas, Fundación para Investigaciones Biológicas, Aplicadas (FIBA), C.C. 1348, 7600, Mar del Plata, Argentina
| | | | | | | |
Collapse
|
171
|
Yuan JS, Tiller KH, Al-Ahmad H, Stewart NR, Stewart CN. Plants to power: bioenergy to fuel the future. TRENDS IN PLANT SCIENCE 2008; 13:421-9. [PMID: 18632303 DOI: 10.1016/j.tplants.2008.06.001] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 05/22/2008] [Accepted: 06/02/2008] [Indexed: 05/18/2023]
Abstract
Bioenergy should play an essential part in reaching targets to replace petroleum-based transportation fuels with a viable alternative, and in reducing long-term carbon dioxide emissions, if environmental and economic sustainability are considered carefully. Here, we review different platforms, crops, and biotechnology-based improvements for sustainable bioenergy. Among the different platforms, there are two obvious advantages to using lignocellulosic biomass for ethanol production: higher net energy gain and lower production costs. However, the use of lignocellulosic ethanol as a viable alternative to petroleum-based transportation fuels largely depends on plant biotechnology breakthroughs. We examine how biotechnology, such as lignin modification, abiotic stress resistance, nutrition usage, in planta expression of cell wall digestion enzymes, biomass production, feedstock establishment, biocontainment of transgenes, metabolic engineering, and basic research, can be used to address the challenges faced by bioenergy crop production.
Collapse
Affiliation(s)
- Joshua S Yuan
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA
| | | | | | | | | |
Collapse
|
172
|
Optimization of metabolic capacity and flux through environmental cues to maximize hydrogen production by the cyanobacterium "Arthrospira (Spirulina) maxima". Appl Environ Microbiol 2008; 74:6102-13. [PMID: 18676712 DOI: 10.1128/aem.01078-08] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Environmental and nutritional conditions that optimize the yield of hydrogen (H(2)) from water using a two-step photosynthesis/fermentation (P/F) process are reported for the hypercarbonate-requiring cyanobacterium "Arthrospira maxima." Our observations lead to four main conclusions broadly applicable to fermentative H(2) production by bacteria: (i) anaerobic H(2) production in the dark from whole cells catalyzed by a bidirectional [NiFe] hydrogenase is demonstrated to occur in two temporal phases involving two distinct metabolic processes that are linked to prior light-dependent production of NADPH (photosynthetic) and dark/anaerobic production of NADH (fermentative), respectively; (ii) H(2) evolution from these reductants represents a major pathway for energy production (ATP) during fermentation by regenerating NAD(+) essential for glycolysis of glycogen and catabolism of other substrates; (iii) nitrate removal during fermentative H(2) evolution is shown to produce an immediate and large stimulation of H(2), as nitrate is a competing substrate for consumption of NAD(P)H, which is distinct from its slower effect of stimulating glycogen accumulation; (iv) environmental and nutritional conditions that increase anaerobic ATP production, prior glycogen accumulation (in the light), and the intracellular reduction potential (NADH/NAD(+) ratio) are shown to be the key variables for elevating H(2) evolution. Optimization of these conditions and culture age increases the H(2) yield from a single P/F cycle using concentrated cells to 36 ml of H(2)/g (dry weight) and a maximum 18% H(2) in the headspace. H(2) yield was found to be limited by the hydrogenase-mediated H(2) uptake reaction.
Collapse
|
173
|
Goldet G, Wait AF, Cracknell JA, Vincent KA, Ludwig M, Lenz O, Friedrich B, Armstrong FA. Hydrogen Production under Aerobic Conditions by Membrane-Bound Hydrogenases from Ralstonia Species. J Am Chem Soc 2008; 130:11106-13. [DOI: 10.1021/ja8027668] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabrielle Goldet
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Annemarie F. Wait
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - James A. Cracknell
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Kylie A. Vincent
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Marcus Ludwig
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Oliver Lenz
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Bärbel Friedrich
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom, and Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany
| |
Collapse
|
174
|
Zhang Z, Pendse ND, Phillips KN, Cotner JB, Khodursky A. Gene expression patterns of sulfur starvation in Synechocystis sp. PCC 6803. BMC Genomics 2008; 9:344. [PMID: 18644144 PMCID: PMC2491639 DOI: 10.1186/1471-2164-9-344] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Accepted: 07/21/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The unicellular cyanobacterium Synechocystis sp. PCC 6803 is a model microbe for studying biochemistry, genetics and molecular biology of photobiological processes. Importance of this bacterium in basic and applied research calls for a systematic, genome-wide description of its transcriptional regulatory capacity. Characteristic transcriptional responses to changes in the growth environment are expected to provide a scaffold for describing the Synechocystis transcriptional regulatory network as well as efficient means for functional annotation of genes in the genome. RESULTS We designed, validated and used Synechocystis genome-wide oligonucleotide (70-mer) microarray (representing 96.7% of all chromosomal ORFs annotated at the time of the beginning of this project) to study transcriptional activity of the cyanobacterial genome in response to sulfur (S) starvation. The microarray data were verified by quantitative RT-PCR. We made five main observations: 1) Transcriptional changes upon sulfate starvation were relatively moderate, but significant and consistent with growth kinetics; 2) S acquisition genes encoding for a high-affinity sulfate transporter were significantly induced, while decreased transcription of genes for phycobilisome, photosystems I and II, cytochrome b6/f, and ATP synthase indicated reduced light-harvesting and photosynthetic activity; 3) S starvation elicited transcriptional responses associated with general growth arrest and stress; 4) A large number of genes regulated by S availability encode hypothetical proteins or proteins of unknown function; 5) Hydrogenase structural and maturation accessory genes were not identified as differentially expressed, even though increased hydrogen evolution was observed. CONCLUSION The expression profiles recorded by using this oligonucleotide-based microarray platform revealed that during transition from the condition of plentiful S to S starvation, Synechocystis undergoes coordinated transcriptional changes, including changes in gene expression whose products are involved in sensing nutrient limitations and tuning bacterial metabolism. The transcriptional profile of the nutrient starvation was dominated by a decrease in abundances of many transcripts. However, these changes were unlikely due to the across-the-board, non-specific shut down of transcription in a condition of growth arrest. Down-regulation of transcripts encoding proteins whose function depends on a cellular S status indicated that the observed repression has a specific regulatory component. The repression of certain S-related genes was paralleled by activation of genes involved in internal and external S scavenging.
Collapse
Affiliation(s)
- Zhigang Zhang
- BioTechnology Institute, 1479 Gortner Avenue, University of Minnesota, St, Paul, MN 55108, USA.
| | | | | | | | | |
Collapse
|
175
|
Brownian dynamics and molecular dynamics study of the association between hydrogenase and ferredoxin from Chlamydomonas reinhardtii. Biophys J 2008; 95:3753-66. [PMID: 18621810 DOI: 10.1529/biophysj.107.127548] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The [FeFe] hydrogenase from the green alga Chlamydomonas reinhardtii can catalyze the reduction of protons to hydrogen gas using electrons supplied from photosystem I and transferred via ferredoxin. To better understand the association of the hydrogenase and the ferredoxin, we have simulated the process over multiple timescales. A Brownian dynamics simulation method gave an initial thorough sampling of the rigid-body translational and rotational phase spaces, and the resulting trajectories were used to compute the occupancy and free-energy landscapes. Several important hydrogenase-ferredoxin encounter complexes were identified from this analysis, which were then individually simulated using atomistic molecular dynamics to provide more details of the hydrogenase and ferredoxin interaction. The ferredoxin appeared to form reasonable complexes with the hydrogenase in multiple orientations, some of which were good candidates for inclusion in a transition state ensemble of configurations for electron transfer.
Collapse
|
176
|
Hu Q, Sommerfeld M, Jarvis E, Ghirardi M, Posewitz M, Seibert M, Darzins A. Microalgal triacylglycerols as feedstocks for biofuel production: perspectives and advances. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 54:621-39. [PMID: 18476868 DOI: 10.1111/j.1365-313x.2008.03492.x] [Citation(s) in RCA: 1715] [Impact Index Per Article: 107.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Microalgae represent an exceptionally diverse but highly specialized group of micro-organisms adapted to various ecological habitats. Many microalgae have the ability to produce substantial amounts (e.g. 20-50% dry cell weight) of triacylglycerols (TAG) as a storage lipid under photo-oxidative stress or other adverse environmental conditions. Fatty acids, the building blocks for TAGs and all other cellular lipids, are synthesized in the chloroplast using a single set of enzymes, of which acetyl CoA carboxylase (ACCase) is key in regulating fatty acid synthesis rates. However, the expression of genes involved in fatty acid synthesis is poorly understood in microalgae. Synthesis and sequestration of TAG into cytosolic lipid bodies appear to be a protective mechanism by which algal cells cope with stress conditions, but little is known about regulation of TAG formation at the molecular and cellular level. While the concept of using microalgae as an alternative and renewable source of lipid-rich biomass feedstock for biofuels has been explored over the past few decades, a scalable, commercially viable system has yet to emerge. Today, the production of algal oil is primarily confined to high-value specialty oils with nutritional value, rather than commodity oils for biofuel. This review provides a brief summary of the current knowledge on oleaginous algae and their fatty acid and TAG biosynthesis, algal model systems and genomic approaches to a better understanding of TAG production, and a historical perspective and path forward for microalgae-based biofuel research and commercialization.
Collapse
Affiliation(s)
- Qiang Hu
- Department of Applied Biological Sciences, Arizona State University Polytechnic Campus, Mesa, AZ 85212, USA
| | | | | | | | | | | | | |
Collapse
|
177
|
Schrader PS, Burrows EH, Ely RL. High-throughput screening assay for biological hydrogen production. Anal Chem 2008; 80:4014-9. [PMID: 18442262 DOI: 10.1021/ac702633q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper describes a screening assay, compatible with high-throughput bioprospecting or molecular biology methods, for assessing biological hydrogen (H2) production. While the assay is adaptable to various physical configurations, we describe its use in a 96-well, microtiter plate format with a lower plate containing H2-producing cyanobacteria strains and controls and an upper, membrane-bottom plate containing a color indicator and a catalyst. H2 produced by cells in the lower plate diffuses through the membrane into the upper plate, causing a color change that can be quantified with a microplate reader. The assay is reproducible, semiquantitative, sensitive down to at least 20 nmol of H2, and largely unaffected by oxygen, carbon dioxide, or volatile fatty acids at levels appropriate to biological systems.
Collapse
Affiliation(s)
- Paul S Schrader
- Department of Chemical Engineering, Yale University, New Haven, Connecticut 06510, USA
| | | | | |
Collapse
|
178
|
Deletion of iscR stimulates recombinant clostridial Fe–Fe hydrogenase activity and H2-accumulation in Escherichia coli BL21(DE3). Appl Microbiol Biotechnol 2008; 78:853-62. [DOI: 10.1007/s00253-008-1377-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/17/2008] [Accepted: 01/17/2008] [Indexed: 10/22/2022]
|
179
|
|
180
|
Regulation of nif gene expression and the energetics of N2 fixation over the diel cycle in a hot spring microbial mat. ISME JOURNAL 2008; 2:364-78. [PMID: 18323780 DOI: 10.1038/ismej.2007.117] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitrogen fixation, a prokaryotic, O2-inhibited process that reduces N2 gas to biomass, is of paramount importance in biogeochemical cycling of nitrogen. We analyzed the levels of nif transcripts of Synechococcus ecotypes, NifH subunit and nitrogenase activity over the diel cycle in the microbial mat of an alkaline hot spring in Yellowstone National Park. The results showed a rise in nif transcripts in the evening, with a subsequent decline over the course of the night. In contrast, immunological data demonstrated that the level of the NifH polypeptide remained stable during the night, and only declined when the mat became oxic in the morning. Nitrogenase activity was low throughout the night; however, it exhibited two peaks, a small one in the evening and a large one in the early morning, when light began to stimulate cyanobacterial photosynthetic activity, but O2 consumption by respiration still exceeded the rate of O2 evolution. Once the irradiance increased to the point at which the mat became oxic, the nitrogenase activity was strongly inhibited. Transcripts for proteins associated with energy-producing metabolisms in the cell also followed diel patterns, with fermentation-related transcripts accumulating at night, photosynthesis- and respiration-related transcripts accumulating during the day and late afternoon, respectively. These results are discussed with respect to the energetics and regulation of N2 fixation in hot spring mats and factors that can markedly influence the extent of N2 fixation over the diel cycle.
Collapse
|
181
|
Hambourger M, Gervaldo M, Svedruzic D, King PW, Gust D, Ghirardi M, Moore AL, Moore TA. [FeFe]-Hydrogenase-Catalyzed H2 Production in a Photoelectrochemical Biofuel Cell. J Am Chem Soc 2008; 130:2015-22. [DOI: 10.1021/ja077691k] [Citation(s) in RCA: 275] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael Hambourger
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Miguel Gervaldo
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Drazenka Svedruzic
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Paul W. King
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Devens Gust
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Maria Ghirardi
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Ana L. Moore
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| | - Thomas A. Moore
- Center for Bioenergy and Photosynthesis and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and Chemical and Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401
| |
Collapse
|
182
|
McDonald TJ, Svedruzic D, Kim YH, Blackburn JL, Zhang SB, King PW, Heben MJ. Wiring-up hydrogenase with single-walled carbon nanotubes. NANO LETTERS 2007; 7:3528-3534. [PMID: 17967044 DOI: 10.1021/nl072319o] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Many envision a future where hydrogen is the centerpiece of a sustainable, carbon-free energy supply. For example, the energy in sunlight may be stored by splitting water into H2 and O2 using inorganic semiconductors and photoelectrochemical approaches or with artificial photosynthetic systems that seek to mimic the light absorption, energy transfer, electron transfer, and redox catalysis that occurs in green plants. Unfortunately, large scale deployment of artificial water-splitting technologies may be impeded by the need for the large amounts of precious metals required to catalyze the multielectron water-splitting reactions. Nature provides a variety of microbes that can activate the dihydrogen bond through the catalytic activity of [NiFe] and [FeFe] hydrogenases, and photobiological approaches to water splitting have been advanced. One may also consider a biohybrid approach; however, it is difficult to interface these sensitive, metalloenzymes to other materials and systems. Here we show that surfactant-suspended carbon single-walled nanotubes (SWNTs) spontaneously self-assemble with [FeFe] hydrogenases in solution to form catalytically active biohybrids. Photoluminescence excitation and Raman spectroscopy studies show that SWNTs act as molecular wires to make electrical contact to the biocatalytic region of hydrogenase. Hydrogenase mediates electron injection into nanotubes having appropriately positioned lowest occupied molecular orbital levels when the H2 partial pressure is varied. The hydrogenase is strongly attached to the SWNTs, so mass transport effects are eliminated and the absolute potential of the electronic levels of the nanotubes can be unambiguously measured. Our findings reveal new nanotube physics and represent the first example of "wiring-up" an hydrogenase with another nanoscale material. This latter advance offers a nonprecious metal route to the design of new biohybrid architectures and building blocks for hydrogen-related technologies.
Collapse
Affiliation(s)
- Timothy J McDonald
- Energy Sciences, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
| | | | | | | | | | | | | |
Collapse
|
183
|
Merchant SS, Prochnik SE, Vallon O, Harris EH, Karpowicz SJ, Witman GB, Terry A, Salamov A, Fritz-Laylin LK, Maréchal-Drouard L, Marshall WF, Qu LH, Nelson DR, Sanderfoot AA, Spalding MH, Kapitonov VV, Ren Q, Ferris P, Lindquist E, Shapiro H, Lucas SM, Grimwood J, Schmutz J, Cardol P, Cerutti H, Chanfreau G, Chen CL, Cognat V, Croft MT, Dent R, Dutcher S, Fernández E, Ferris P, Fukuzawa H, González-Ballester D, González-Halphen D, Hallmann A, Hanikenne M, Hippler M, Inwood W, Jabbari K, Kalanon M, Kuras R, Lefebvre PA, Lemaire SD, Lobanov AV, Lohr M, Manuell A, Meier I, Mets L, Mittag M, Mittelmeier T, Moroney JV, Moseley J, Napoli C, Nedelcu AM, Niyogi K, Novoselov SV, Paulsen IT, Pazour G, Purton S, Ral JP, Riaño-Pachón DM, Riekhof W, Rymarquis L, Schroda M, Stern D, Umen J, Willows R, Wilson N, Zimmer SL, Allmer J, Balk J, Bisova K, Chen CJ, Elias M, Gendler K, Hauser C, Lamb MR, Ledford H, Long JC, Minagawa J, Page MD, Pan J, Pootakham W, Roje S, Rose A, Stahlberg E, Terauchi AM, Yang P, Ball S, Bowler C, Dieckmann CL, Gladyshev VN, Green P, Jorgensen R, Mayfield S, Mueller-Roeber B, Rajamani S, Sayre RT, Brokstein P, Dubchak I, Goodstein D, Hornick L, Huang YW, Jhaveri J, Luo Y, Martínez D, Ngau WCA, Otillar B, Poliakov A, Porter A, Szajkowski L, Werner G, Zhou K, Grigoriev IV, Rokhsar DS, Grossman AR. The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science 2007; 318:245-50. [PMID: 17932292 PMCID: PMC2875087 DOI: 10.1126/science.1143609] [Citation(s) in RCA: 1797] [Impact Index Per Article: 105.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.
Collapse
Affiliation(s)
- Sabeeha S. Merchant
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Simon E. Prochnik
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Olivier Vallon
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | | | - Steven J. Karpowicz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - George B. Witman
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Astrid Terry
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Asaf Salamov
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Lillian K. Fritz-Laylin
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
| | | | - Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA 94143, USA
| | - Liang-Hu Qu
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - David R. Nelson
- Department of Molecular Sciences and Center of Excellence in Genomics and Bioinformatics, University of Tennessee, Memphis, TN 38163, USA
| | - Anton A. Sanderfoot
- Department of Plant Biology, University of Minnesota, St. Paul MN 55108, USA
| | - Martin H. Spalding
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | | | - Qinghu Ren
- The Institute for Genomic Research, Rockville, MD 20850, USA
| | - Patrick Ferris
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Erika Lindquist
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Harris Shapiro
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Susan M. Lucas
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jane Grimwood
- Stanford Human Genome Center, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Jeremy Schmutz
- Stanford Human Genome Center, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Pierre Cardol
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
- Plant Biology Institute, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Heriberto Cerutti
- University of Nebraska-Lincoln, School of Biological Sciences–Plant Science Initiative, Lincoln, NE 68588, USA
| | - Guillaume Chanfreau
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Chun-Long Chen
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - Valérie Cognat
- Institut de Biologie Moléculaire des Plantes, CNRS, 67084 Strasbourg Cedex, France
| | - Martin T. Croft
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Rachel Dent
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Susan Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Campus de Rabanales, 14071 Córdoba, Spain
| | - Patrick Ferris
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | | | - Diego González-Halphen
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México 04510 DF, Mexico
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, D-33615 Bielefeld, Germany
| | - Marc Hanikenne
- Plant Biology Institute, Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Michael Hippler
- Department of Biology, Institute of Plant Biochemistry and Biotechnology, University of Münster, 48143 Münster, Germany
| | - William Inwood
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Kamel Jabbari
- CNRS UMR 8186, Département de Biologie, Ecole Normale Supérieure, 75230 Paris, France
| | - Ming Kalanon
- Plant Cell Biology Research Centre, The School of Botany, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia
| | - Richard Kuras
- CNRS, UMR 7141, CNRS/Université Paris 6, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Paul A. Lefebvre
- Department of Plant Biology, University of Minnesota, St. Paul MN 55108, USA
| | - Stéphane D. Lemaire
- Institut de Biotechnologie des Plantes, UMR 8618, CNRS/Université Paris-Sud, Orsay, France
| | - Alexey V. Lobanov
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Martin Lohr
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität, 55099 Mainz, Germany
| | - Andrea Manuell
- Department of Cell Biology and Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - Iris Meier
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Laurens Mets
- Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Maria Mittag
- Institut für Allgemeine Botanik und Pflanzenphysiologie, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany
| | - Telsa Mittelmeier
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - James V. Moroney
- Department of Biological Science, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Jeffrey Moseley
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| | - Carolyn Napoli
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Aurora M. Nedelcu
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada E3B 6E1
| | - Krishna Niyogi
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Sergey V. Novoselov
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Ian T. Paulsen
- The Institute for Genomic Research, Rockville, MD 20850, USA
| | - Greg Pazour
- Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Saul Purton
- Department of Biology, University College London, London WC1E 6BT, UK
| | - Jean-Philippe Ral
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR8576 CNRS/USTL, IFR 118, Université des Sciences et Technologies de Lille, Cedex, France
| | | | - Wayne Riekhof
- Department of Medicine, National Jewish Medical and Research Center, Denver, CO 80206, USA
| | - Linda Rymarquis
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Michael Schroda
- Institute of Biology II/Plant Biochemistry, 79104 Freiburg, Germany
| | - David Stern
- Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853, USA
| | - James Umen
- Plant Biology Laboratory, Salk Institute, La Jolla, CA 92037, USA
| | - Robert Willows
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney 2109, Australia
| | - Nedra Wilson
- Department of Anatomy and Cell Biology, Oklahoma State University, Center for Health Sciences, Tulsa, OK 74107, USA
| | - Sara Lana Zimmer
- Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853, USA
| | - Jens Allmer
- Izmir Ekonomi Universitesi, 35330 Balcova-Izmir Turkey
| | - Janneke Balk
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Katerina Bisova
- Institute of Microbiology, Czech Academy of Sciences, Czech Republic
| | - Chong-Jian Chen
- Biotechnology Research Center, Zhongshan University, Guangzhou 510275, China
| | - Marek Elias
- Department of Plant Physiology, Faculty of Sciences, Charles University, 128 44 Prague 2, Czech Republic
| | - Karla Gendler
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Charles Hauser
- Bioinformatics Program, St. Edward's University, Austin, TX 78704, USA
| | - Mary Rose Lamb
- Department of Biology, University of Puget Sound, Tacoma, WA 98407, USA
| | - Heidi Ledford
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Joanne C. Long
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jun Minagawa
- Institute of Low-Temperature Science, Hokkaido University, 060-0819, Japan
| | - M. Dudley Page
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Junmin Pan
- Department of Biology, Tsinghua University, Beijing, China 100084
| | - Wirulda Pootakham
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| | - Sanja Roje
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | | | - Eric Stahlberg
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Aimee M. Terauchi
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Pinfen Yang
- Department of Biology, Marquette University, Milwaukee, WI 53233, USA
| | - Steven Ball
- UMR8576 CNRS, Laboratory of Biological Chemistry, 59655 Villeneuve d'Ascq, France
| | - Chris Bowler
- CNRS UMR 8186, Département de Biologie, Ecole Normale Supérieure, 75230 Paris, France
- Cell Signaling Laboratory, Stazione Zoologica, I 80121 Naples, Italy
| | - Carol L. Dieckmann
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Vadim N. Gladyshev
- Department of Biochemistry, N151 Beadle Center, University of Nebraska, Lincoln, NE 68588–0664, USA
| | - Pamela Green
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Richard Jorgensen
- Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Stephen Mayfield
- Department of Cell Biology and Skaggs Institute for Chemical Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | | | - Sathish Rajamani
- Graduate Program in Biophysics, Ohio State University, Columbus, OH 43210, USA
| | - Richard T. Sayre
- PCMB and Plant Biotechnology Center, Ohio State University, Columbus, OH 43210, USA
| | - Peter Brokstein
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Inna Dubchak
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - David Goodstein
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Leila Hornick
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Y. Wayne Huang
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Jinal Jhaveri
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Yigong Luo
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Diego Martínez
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Wing Chi Abby Ngau
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Bobby Otillar
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Alexander Poliakov
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Aaron Porter
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Lukasz Szajkowski
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Gregory Werner
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Kemin Zhou
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Igor V. Grigoriev
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Daniel S. Rokhsar
- U.S. Department of Energy, Joint Genome Institute, Walnut Creek, CA 94598, USA
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA94720, USA
| | - Arthur R. Grossman
- Department of Plant Biology, Carnegie Institution, Stanford, CA 94306, USA
| |
Collapse
|
184
|
Vignais PM, Billoud B. Occurrence, Classification, and Biological Function of Hydrogenases: An Overview. Chem Rev 2007; 107:4206-72. [PMID: 17927159 DOI: 10.1021/cr050196r] [Citation(s) in RCA: 1034] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Paulette M. Vignais
- CEA Grenoble, Laboratoire de Biochimie et Biophysique des Systèmes Intégrés, UMR CEA/CNRS/UJF 5092, Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), 17 rue des Martyrs, 38054 Grenoble cedex 9, France, and Atelier de BioInformatique Université Pierre et Marie Curie (Paris 6), 12 rue Cuvier, 75005 Paris, France
| | - Bernard Billoud
- CEA Grenoble, Laboratoire de Biochimie et Biophysique des Systèmes Intégrés, UMR CEA/CNRS/UJF 5092, Institut de Recherches en Technologies et Sciences pour le Vivant (iRTSV), 17 rue des Martyrs, 38054 Grenoble cedex 9, France, and Atelier de BioInformatique Université Pierre et Marie Curie (Paris 6), 12 rue Cuvier, 75005 Paris, France
| |
Collapse
|
185
|
Makarova VV, Kosourov S, Krendeleva TE, Semin BK, Kukarskikh GP, Rubin AB, Sayre RT, Ghirardi ML, Seibert M. Photoproduction of hydrogen by sulfur-deprived C. reinhardtii mutants with impaired photosystem II photochemical activity. PHOTOSYNTHESIS RESEARCH 2007; 94:79-89. [PMID: 17701084 DOI: 10.1007/s11120-007-9219-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 07/03/2007] [Indexed: 05/16/2023]
Abstract
Photoproduction of H2 was examined in a series of sulfur-deprived Chlamydomonas reinhardtii D1-R323 mutants with progressively impaired PSII photochemical activity. In the R323H, R323D, and R323E D1 mutants, replacement of arginine affects photosystem II (PSII) function, as demonstrated by progressive decreases in O2-evolving activity and loss of PSII photochemical activity. Significant changes in PSII activity were found when the arginine residue was replaced by negatively charged amino acid residues (R323D and R323E). However, the R323H (positively charged or neutral, depending on the ambient pH) mutant had minimal changes in PSII activity. The R323H, R323D, and R323E mutants and the pseudo-wild-type (pWt) with restored PSII function were used to study the effects of sulfur deprivation on H2-production activity. All of these mutants exhibited significant changes in the normal parameters associated with the H2-photoproduction process, such as a shorter aerobic phase, lower accumulation of starch, a prolonged anaerobic phase observed before the onset of H2-production, a shorter duration of H2-production, lower H2 yields compared to the pWt control, and slightly higher production of dark fermentation products such as acetate and formate. The more compromised the PSII photochemical activity, the more dramatic was the effect of sulfur deprivation on the H2-production process, which depends both on the presence of residual PSII activity and the amount of stored starch.
Collapse
Affiliation(s)
- Valeria V Makarova
- National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
186
|
Hankamer B, Lehr F, Rupprecht J, Mussgnug JH, Posten C, Kruse O. Photosynthetic biomass and H2 production by green algae: from bioengineering to bioreactor scale-up. PHYSIOLOGIA PLANTARUM 2007; 131:10-21. [PMID: 18251920 DOI: 10.1111/j.1399-3054.2007.00924.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The development of clean borderless fuels is of vital importance to human and environmental health and global prosperity. Currently, fuels make up approximately 67% of the global energy market (total market = 15 TW year(-1)) (Hoffert et al. 1998). In contrast, global electricity demand accounts for only 33% (Hoffert et al. 1998). Yet, despite the importance of fuels, almost all CO(2) free energy production systems under development are designed to drive electricity generation (e.g. clean-coal technology, nuclear, photovoltaic, wind, geothermal, wave and hydroelectric). In contrast, and indeed almost uniquely, biofuels also target the much larger fuel market and so in the future will play an increasingly important role in maintaining energy security (Lal 2005). Currently, the main biofuels that are at varying stages of development include bio-ethanol, liquid carbohydrates [e.g. biodiesel or biomass to liquid (BTL) products], biomethane and bio-H(2). This review is focused on placing bio-H(2) production processes into the context of the current biofuels market and summarizing advances made both at the level of bioengineering and bioreactor design.
Collapse
Affiliation(s)
- Ben Hankamer
- Institute for Molecular Bioscience, University of Queensland, St Lucia Campus, Brisbane, Queensland 4072, Australia
| | | | | | | | | | | |
Collapse
|
187
|
Mus F, Dubini A, Seibert M, Posewitz MC, Grossman AR. Anaerobic acclimation in Chlamydomonas reinhardtii: anoxic gene expression, hydrogenase induction, and metabolic pathways. J Biol Chem 2007; 282:25475-86. [PMID: 17565990 DOI: 10.1074/jbc.m701415200] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Both prokaryotic and eukaryotic photosynthetic microbes experience conditions of anoxia, especially during the night when photosynthetic activity ceases. In Chlamydomonas reinhardtii, dark anoxia is characterized by the activation of an extensive set of fermentation pathways that act in concert to provide cellular energy, while limiting the accumulation of potentially toxic fermentative products. Metabolite analyses, quantitative PCR, and high density Chlamydomonas DNA microarrays were used to monitor changes in metabolite accumulation and gene expression during acclimation of the cells to anoxia. Elevated levels of transcripts encoding proteins associated with the production of H2, organic acids, and ethanol were observed in congruence with the accumulation of fermentation products. The levels of over 500 transcripts increased significantly during acclimation of the cells to anoxic conditions. Among these were transcripts encoding transcription/translation regulators, prolyl hydroxylases, hybrid cluster proteins, proteases, transhydrogenase, catalase, and several putative proteins of unknown function. Overall, this study uses metabolite, genomic, and transcriptome data to provide genome-wide insights into the regulation of the complex metabolic networks utilized by Chlamydomonas under the anaerobic conditions associated with H2 production.
Collapse
Affiliation(s)
- Florence Mus
- Department of Plant Biology, Carnegie Institution, Stanford, California 94305, USA
| | | | | | | | | |
Collapse
|