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Title: Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium

Abstract

Nitrogenase is an ATP-requiring enzyme capable of carrying out multielectron reductions of inert molecules. A purified remodeled nitrogenase containing two amino acid substitutions near the site of its FeMo cofactor was recently described as having the capacity to reduce carbon dioxide (CO 2) to methane (CH 4). Here, we developed the anoxygenic phototroph, Rhodopseudomonas palustris, as a biocatalyst capable of light-driven CO 2 reduction to CH 4 in vivo using this remodeled nitrogenase. Conversion of CO 2 to CH 4 by R. palustris required constitutive expression of nitrogenase, which was achieved by using a variant of the transcription factor NifA that is able to activate expression of nitrogenase under all growth conditions. Also, light was required for generation of ATP by cyclic photophosphorylation. CH 4 production by R. palustris could be controlled by manipulating the distribution of electrons and energy available to nitrogenase. Furthermore, this work shows the feasibility of using microbes to generate hydrocarbons from CO 2 in one enzymatic step using light energy.

Authors:
 [1];  [1];  [2];  [2];  [2];  [3];  [2]; ORCiD logo [1]
  1. Univ. of Washington, Seattle, WA (United States)
  2. Utah State Univ., Logan, UT (United States)
  3. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
Publication Date:
Research Org.:
Utah State Univ., Logan, UT (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1319953
Alternate Identifier(s):
OSTI ID: 1436487
Grant/Contract Number:
SC0012518
Resource Type:
Journal Article: Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 36; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; nitrogenase; Rhodopseudomonas; bioenergy; methane; engineered bacterium

Citation Formats

Fixen, Kathryn R., Zheng, Yanning, Harris, Derek F., Shaw, Sudipta, Yang, Zhi -Yong, Dean, Dennis R., Seefeldt, Lance C., and Harwood, Caroline S.. Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium. United States: N. p., 2016. Web. doi:10.1073/pnas.1611043113.
Fixen, Kathryn R., Zheng, Yanning, Harris, Derek F., Shaw, Sudipta, Yang, Zhi -Yong, Dean, Dennis R., Seefeldt, Lance C., & Harwood, Caroline S.. Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium. United States. doi:10.1073/pnas.1611043113.
Fixen, Kathryn R., Zheng, Yanning, Harris, Derek F., Shaw, Sudipta, Yang, Zhi -Yong, Dean, Dennis R., Seefeldt, Lance C., and Harwood, Caroline S.. Mon . "Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium". United States. doi:10.1073/pnas.1611043113.
@article{osti_1319953,
title = {Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium},
author = {Fixen, Kathryn R. and Zheng, Yanning and Harris, Derek F. and Shaw, Sudipta and Yang, Zhi -Yong and Dean, Dennis R. and Seefeldt, Lance C. and Harwood, Caroline S.},
abstractNote = {Nitrogenase is an ATP-requiring enzyme capable of carrying out multielectron reductions of inert molecules. A purified remodeled nitrogenase containing two amino acid substitutions near the site of its FeMo cofactor was recently described as having the capacity to reduce carbon dioxide (CO2) to methane (CH4). Here, we developed the anoxygenic phototroph, Rhodopseudomonas palustris, as a biocatalyst capable of light-driven CO2 reduction to CH4 in vivo using this remodeled nitrogenase. Conversion of CO2 to CH4 by R. palustris required constitutive expression of nitrogenase, which was achieved by using a variant of the transcription factor NifA that is able to activate expression of nitrogenase under all growth conditions. Also, light was required for generation of ATP by cyclic photophosphorylation. CH4 production by R. palustris could be controlled by manipulating the distribution of electrons and energy available to nitrogenase. Furthermore, this work shows the feasibility of using microbes to generate hydrocarbons from CO2 in one enzymatic step using light energy.},
doi = {10.1073/pnas.1611043113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 36,
volume = 113,
place = {United States},
year = {Mon Aug 22 00:00:00 EDT 2016},
month = {Mon Aug 22 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1611043113

Citation Metrics:
Cited by: 3works
Citation information provided by
Web of Science

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  • Nitrogenase is an ATP-requiring enzyme capable of carrying out multielectron reductions of inert molecules. A purified remodeled nitrogenase containing two amino acid substitutions near the site of its FeMo cofactor was recently described as having the capacity to reduce carbon dioxide (CO 2) to methane (CH 4). Here, we developed the anoxygenic phototroph, Rhodopseudomonas palustris, as a biocatalyst capable of light-driven CO 2 reduction to CH 4 in vivo using this remodeled nitrogenase. Conversion of CO 2 to CH 4 by R. palustris required constitutive expression of nitrogenase, which was achieved by using a variant of the transcription factor NifAmore » that is able to activate expression of nitrogenase under all growth conditions. Also, light was required for generation of ATP by cyclic photophosphorylation. CH 4 production by R. palustris could be controlled by manipulating the distribution of electrons and energy available to nitrogenase. Furthermore, this work shows the feasibility of using microbes to generate hydrocarbons from CO 2 in one enzymatic step using light energy.« less
  • Nitrogenase proteins were isolated from cultures of the photosynthetic bacterium Rhodopseudomonas capsulata grown on a limiting amount of ammonia. Under these conditions, the nitrogenase N/sub 2/ase A was active in vivo, and nitrogenase activity in vitro was not dependent upon manganese and the activating factor. The nitrogenase proteins were also isolated from nitrogen-limited cultures in which the in vivo nitrogenase activity had been stopped by an ammonia shock. This nitrogenase activity, N/sub 2/ase R, showed an in vitro requirement for manganese and the activating factor for maximal activity. The Mo-Fe protein (dinitrogenase) was composed of two dissimilar subunits with molecularmore » weights of 55,000 and 59,500; the Fe protein (dinitrogenase reductase), from either type of culture, was composed of a single subunit (molecular weight, 33,500). The metal and acid labile sulfur contents of both nitrogenase proteins were similar to those found for previously isolated nitrogenases. The Fe proteins from both N/sub 2/ase a and N/sub 2/ase R contained phosphate and ribose, 2 mol of each per mol of N/sub 2/ase R Fe protein contained about 1 mol per mol of an adenine-like molecule, whereas the N/sub 2/ase A Fe protein content of this compound was insignificant. These results are compared with various models previously presented for the short-term regulation of nitrogenase activity in the photosynthetic bacteria.« less
  • The addition of NH[sub 4]Cl at concentrations of more than 1 mM completely inhibited nitrogenase-dependent hydrogen evolution using 1 mM succinate as a substrate in the marine photosynthetic bacterium Rhodopseudomonas sp. strain W-1S. However, cells could derepress nitrogenase within 6 h in the presence of NH[sub 4]Cl. The inhibition by 1 mM NH[sub 4]Cl was removed by increasing the concentration of the substrate for hydrogen evolution. The addition of L-methionine-D,L-sulfoximine (MSX), an inhibitor of glutamine synthetase (GS), also removed the inhibition by 1 mM NH[sub 4]Cl. These results indicated that under an argon gas phase, nitrogenase-dependent hydrogen evolution is inhibitedmore » by ATP-consuming GS activity in the presence of NH[sub 4]Cl. The authors isolated a mutant strain, CR-8, which is capable of active hydrogen evolution in the presence of 1 mM NH[sub 4]Cl. 7 refs., 5 figs.« less