skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Energy Conservation via Hydrogen Cycling in the Methanogenic Archaeon Methanosarcina barkeri

Abstract

Energy conservation via hydrogen cycling, which generates proton motive force by intracellular H 2production coupled to extracellular consumption, has been controversial since it was first proposed in 1981. It was hypothesized that the methanogenic archaeonMethanosarcina barkeriis capable of energy conservation via H 2cycling, based on genetic data that suggest that H 2is a preferred, but nonessential, intermediate in the electron transport chain of this organism. Here, we characterize a series of hydrogenase mutants to provide direct evidence of H 2cycling.M. barkeriproduces H 2during growth on methanol, a phenotype that is lost upon mutation of the cytoplasmic hydrogenase encoded byfrhADGB, although low levels of H 2, attributable to the Ech hydrogenase, accumulate during stationary phase. In contrast, mutations that conditionally inactivate the extracellular Vht hydrogenase are lethal when expression of thevhtGACDoperon is repressed. Under these conditions, H 2accumulates, with concomitant cessation of methane production and subsequent cell lysis, suggesting that the inability to recapture extracellular H 2is responsible for the lethal phenotype. Consistent with this interpretation, double mutants that lack both Vht and Frh are viable. Thus, when intracellular hydrogen production is abrogated, loss of extracellular H 2 consumption is no longer lethal. The common occurrence of both intracellular and extracellular hydrogenasesmore » in anaerobic microorganisms suggests that this unusual mechanism of energy conservation may be widespread in nature. IMPORTANCEATP is required by all living organisms to facilitate essential endergonic reactions required for growth and maintenance. Although synthesis of ATP by substrate-level phosphorylation is widespread and significant, most ATP is made via the enzyme ATP synthase, which is energized by transmembrane chemiosmotic gradients. Therefore, establishing this gradient across the membrane is of central importance to sustaining life. Experimental validation of H 2cycling adds to a short list of mechanisms for generating a transmembrane electrochemical gradient that is likely to be widespread, especially among anaerobic microorganisms.« less

Authors:
 [1];  [2]; ORCiD logo [2];  [3]
  1. Univ. of California, Irvine, CA (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States)
  2. Univ. of Illinois, Champaign, IL (United States)
  3. Univ. of California, Irvine, CA (United States)
Publication Date:
Research Org.:
Univ. of Illinois at Urbana-Champaign, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1510523
Alternate Identifier(s):
OSTI ID: 1595341
Grant/Contract Number:  
FG02-02ER15296
Resource Type:
Accepted Manuscript
Journal Name:
mBio (Online)
Additional Journal Information:
Journal Name: mBio (Online); Journal Volume: 9; Journal Issue: 4; Journal ID: ISSN 2150-7511
Publisher:
American Society for Microbiology
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Methanosarcina; energy conservation; hydrogenase; methanogenesis

Citation Formats

Kulkarni, Gargi, Mand, Thomas D., Metcalf, William W., and Ribbe, Markus W. Energy Conservation via Hydrogen Cycling in the Methanogenic Archaeon Methanosarcina barkeri. United States: N. p., 2018. Web. doi:10.1128/mbio.01256-18.
Kulkarni, Gargi, Mand, Thomas D., Metcalf, William W., & Ribbe, Markus W. Energy Conservation via Hydrogen Cycling in the Methanogenic Archaeon Methanosarcina barkeri. United States. doi:10.1128/mbio.01256-18.
Kulkarni, Gargi, Mand, Thomas D., Metcalf, William W., and Ribbe, Markus W. Tue . "Energy Conservation via Hydrogen Cycling in the Methanogenic Archaeon Methanosarcina barkeri". United States. doi:10.1128/mbio.01256-18. https://www.osti.gov/servlets/purl/1510523.
@article{osti_1510523,
title = {Energy Conservation via Hydrogen Cycling in the Methanogenic Archaeon Methanosarcina barkeri},
author = {Kulkarni, Gargi and Mand, Thomas D. and Metcalf, William W. and Ribbe, Markus W.},
abstractNote = {Energy conservation via hydrogen cycling, which generates proton motive force by intracellular H2production coupled to extracellular consumption, has been controversial since it was first proposed in 1981. It was hypothesized that the methanogenic archaeonMethanosarcina barkeriis capable of energy conservation via H2cycling, based on genetic data that suggest that H2is a preferred, but nonessential, intermediate in the electron transport chain of this organism. Here, we characterize a series of hydrogenase mutants to provide direct evidence of H2cycling.M. barkeriproduces H2during growth on methanol, a phenotype that is lost upon mutation of the cytoplasmic hydrogenase encoded byfrhADGB, although low levels of H2, attributable to the Ech hydrogenase, accumulate during stationary phase. In contrast, mutations that conditionally inactivate the extracellular Vht hydrogenase are lethal when expression of thevhtGACDoperon is repressed. Under these conditions, H2accumulates, with concomitant cessation of methane production and subsequent cell lysis, suggesting that the inability to recapture extracellular H2is responsible for the lethal phenotype. Consistent with this interpretation, double mutants that lack both Vht and Frh are viable. Thus, when intracellular hydrogen production is abrogated, loss of extracellular H2 consumption is no longer lethal. The common occurrence of both intracellular and extracellular hydrogenases in anaerobic microorganisms suggests that this unusual mechanism of energy conservation may be widespread in nature. IMPORTANCEATP is required by all living organisms to facilitate essential endergonic reactions required for growth and maintenance. Although synthesis of ATP by substrate-level phosphorylation is widespread and significant, most ATP is made via the enzyme ATP synthase, which is energized by transmembrane chemiosmotic gradients. Therefore, establishing this gradient across the membrane is of central importance to sustaining life. Experimental validation of H2cycling adds to a short list of mechanisms for generating a transmembrane electrochemical gradient that is likely to be widespread, especially among anaerobic microorganisms.},
doi = {10.1128/mbio.01256-18},
journal = {mBio (Online)},
number = 4,
volume = 9,
place = {United States},
year = {2018},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

Figures / Tables:

FIG 1 FIG 1: Putative H2 cycling electron transport chain of M. barkeri. Growth on C1 substrates generates reduced cofactor F420 (F420red), which is a hydride carrying cofactor analogous to NADH, and the reduced form of the small electron-carrying protein ferredoxin (Fdred). During aceticlastic methanogenesis, only Fdred is produced. These reduced electronmore » carriers are reoxidized in the cytoplasm by the Frh and Ech hydrogenases, respectively, with concomitant consumption of protons to produce molecular H2. H2 subsequently diffuses out of the cell where it is reoxidized by the Vht hydrogenase, which has an active site located on the outer face of the cell membrane. This reaction releases protons on the outside of the cell and produces reduced methanophenazine (MPH2), a membrane-bound electron carrier analogous to ubiquinone. MPH2 subsequently delivers electrons to the enzyme heterodisulfide reductase (Hdr), which serves as the terminal step in the Methanosarcina electron transport chain. This final reaction regenerates coenzyme B (CoB-SH) and coenzyme M (CoM-SH) from the mixed disulfide (CoM-S-S-CoB), which is produced from the free thiol cofactors during methanogenic metabolism. Electron (e) flow and scalar protons (H+) are shown in red. It should be noted that M. barkeri can also reoxidize F420red using the membrane-bound, proton-pumping F420-dehydrogenase (Fpo). Thus, the cell has a branched electron transport chain, and therefore, it is not dependent on H2 cycling during growth on methylotrophic substrates (16); however, both pathways for electron transport from F420 have identical levels of energy conservation: namely, 4 H+/2e . It should also be noted that the Ech hydrogenase acts as a proton pump in addition to its role in H2 cycling, thus electron transport from Fdred during methylotrophic and aceticlastic methanogenesis conserves 6H+/2e. Individual subunits of the various enzymes are indicated by capital letters (e.g., A, B, C. . .).« less

Save / Share:

Works referenced in this record:

Development of a Markerless Genetic Exchange Method for Methanosarcina acetivorans C2A and Its Use in Construction of New Genetic Tools for Methanogenic Archaea
journal, March 2004


Hydrogen is a preferred intermediate in the energy-conserving electron transport chain of Methanosarcina barkeri
journal, September 2009

  • Kulkarni, Gargi; Kridelbaugh, Donna M.; Guss, Adam M.
  • Proceedings of the National Academy of Sciences, Vol. 106, Issue 37
  • DOI: 10.1073/pnas.0905914106

Analysis of the vhoGAC and vhtGAC Operons from Methanosarcina mazei Strain Go1, Both Encoding a Membrane-bound Hydrogenase and a Cytochrome b
journal, January 1995


Molecular, genetic, and biochemical characterization of the serC gene of Methanosarcina barkeri Fusaro.
journal, October 1996


A unified model describing the role of hydrogen in the growth ofDesulfovibrio vulgaris under different environmental conditions
journal, September 1998


The F 420 H 2 Dehydrogenase from Methanosarcina mazei Is a Redox-driven Proton Pump Closely Related to NADH Dehydrogenases
journal, April 2000

  • Bäumer, Sebastian; Ide, Tina; Jacobi, Carsten
  • Journal of Biological Chemistry, Vol. 275, Issue 24
  • DOI: 10.1074/jbc.M000650200

Differences in Hydrogenase Gene Expression between Methanosarcina acetivorans and Methanosarcina barkeri
journal, February 2009

  • Guss, A. M.; Kulkarni, G.; Metcalf, W. W.
  • Journal of Bacteriology, Vol. 191, Issue 8
  • DOI: 10.1128/JB.00563-08

Purification and catalytic properties of Ech hydrogenase from Methanosarcina barkeri
journal, October 1999


Bacterial Rhodopsin: Evidence for a New Type of Phototrophy in the Sea
journal, September 2000


Hydrogen metabolism during methanogenesis from acetate by Methanosarcina barkeri
journal, February 1987


Hydrogenase, Electron-Transfer Proteins, and Energy Coupling in the Sulfate-Reducing Bacteria Desulfovibrio
journal, October 1984


A direct demonstration of hydrogen cycling by Desulfovibrio vulgaris employing membrane-inlet mass spectrometry
journal, February 1987


The Na+-translocating methyltransferase complex from methanogenic archaea
journal, May 2001

  • Gottschalk, Gerhard; Thauer, Rudolf K.
  • Biochimica et Biophysica Acta (BBA) - Bioenergetics, Vol. 1505, Issue 1
  • DOI: 10.1016/S0005-2728(00)00274-7

[FeFe]- and [NiFe]-hydrogenase diversity, mechanism, and maturation
journal, June 2015

  • Peters, John W.; Schut, Gerrit J.; Boyd, Eric S.
  • Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, Vol. 1853, Issue 6
  • DOI: 10.1016/j.bbamcr.2014.11.021

Formate-Dependent H2 Production by the Mesophilic Methanogen Methanococcus maripaludis
journal, September 2008

  • Lupa, B.; Hendrickson, E. L.; Leigh, J. A.
  • Applied and Environmental Microbiology, Vol. 74, Issue 21
  • DOI: 10.1128/AEM.01455-08

The Membrane-Bound Electron Transport System of Methanosarcina Species
journal, February 2004


Methanogenic archaea: ecologically relevant differences in energy conservation
journal, June 2008

  • Thauer, Rudolf K.; Kaster, Anne-Kristin; Seedorf, Henning
  • Nature Reviews Microbiology, Vol. 6, Issue 8
  • DOI: 10.1038/nrmicro1931

Genetic analysis of the archaeon Methanosarcina barkeri Fusaro reveals a central role for Ech hydrogenase and ferredoxin in methanogenesis and carbon fixation
journal, April 2002

  • Meuer, J.; Kuettner, H. C.; Zhang, J. K.
  • Proceedings of the National Academy of Sciences, Vol. 99, Issue 8
  • DOI: 10.1073/pnas.072615499

Hydrogen inhibition of acetate metabolism and kinetics of hydrogen consumption by Methanosarcina thermophila TM-1
journal, December 1991

  • Ahring, BirgitteK.; Westermann, Peter; Mah, RobertA.
  • Archives of Microbiology, Vol. 157, Issue 1
  • DOI: 10.1007/BF00245332

Two F 420 -reducing hydrogenases in Methanosarcina barkeri
journal, February 1998


Properties of a hydrogen-inhibited mutant of Desulfovibrio desulfuricans ATCC 27774.
journal, March 1987


Analysis of hydrogen metabolism in Methanosarcina barkeri: Regulation of hydrogenase and role of CO-dehydrogenase in H2 production
journal, May 1987


Novel regulatory mutants of the phosphate regulon in Escherichia coli K-12
journal, September 1986


The hydrogenases of Geobacter sulfurreducens: a comparative genomic perspective
journal, April 2005


Inhibition of membrane-bound electron transport of the methanogenic archaeon Methanosarcina mazei Gö1 by diphenyleneiodonium
journal, January 1999


Hydrogen cycling as a general mechanism for energy coupling in the sulfate-reducing bacteria, Desulfovibrio sp.
journal, September 1981


The Effect of Hydrogen on the Growth of Desulfovibrio vulgaris (Hildenborough) on Lactate
journal, December 1986


A genetic system for Archaea of the genus Methanosarcina: Liposome-mediated transformation and construction of shuttle vectors
journal, March 1997

  • Metcalf, W. W.; Zhang, J. K.; Apolinario, E.
  • Proceedings of the National Academy of Sciences, Vol. 94, Issue 6
  • DOI: 10.1073/pnas.94.6.2626

    Works referencing / citing this record:

    Increasing sulfate levels show a differential impact on synthetic communities comprising different methanogens and a sulfate reducer
    journal, May 2019

    • Chen, Jing; Wade, Matthew J.; Dolfing, Jan
    • Journal of The Royal Society Interface, Vol. 16, Issue 154
    • DOI: 10.1098/rsif.2019.0129

      Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.