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Tu W, Thompson IP, Huang WE. Engineering bionanoreactor in bacteria for efficient hydrogen production. Proc Natl Acad Sci U S A 2024; 121:e2404958121. [PMID: 38985767 DOI: 10.1073/pnas.2404958121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 06/14/2024] [Indexed: 07/12/2024] Open
Abstract
Hydrogen production through water splitting is a vital strategy for renewable and sustainable clean energy. In this study, we developed an approach integrating nanomaterial engineering and synthetic biology to establish a bionanoreactor system for efficient hydrogen production. The periplasmic space (20 to 30 nm) of an electroactive bacterium, Shewanella oneidensis MR-1, was engineered to serve as a bionanoreactor to enhance the interaction between electrons and protons, catalyzed by hydrogenases for hydrogen generation. To optimize electron transfer, we used the microbially reduced graphene oxide (rGO) to coat the electrode, which improved the electron transfer from the electrode to the cells. Native MtrCAB protein complex on S. oneidensis and self-assembled iron sulfide (FeS) nanoparticles acted in tandem to facilitate electron transfer from an electrode to the periplasm. To enhance proton transport, S. oneidensis MR-1 was engineered to express Gloeobacter rhodopsin (GR) and the light-harvesting antenna canthaxanthin. This led to efficient proton pumping when exposed to light, resulting in a 35.6% increase in the rate of hydrogen production. The overexpression of native [FeFe]-hydrogenase further improved the hydrogen production rate by 56.8%. The bionanoreactor engineered in S. oneidensis MR-1 achieved a hydrogen yield of 80.4 μmol/mg protein/day with a Faraday efficiency of 80% at a potential of -0.75 V. This periplasmic bionanoreactor combines the strengths of both nanomaterial and biological components, providing an efficient approach for microbial electrosynthesis.
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Affiliation(s)
- Weiming Tu
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Ian P Thompson
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Wei E Huang
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
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Hour C, Chuon K, Song MC, Shim JG, Cho SG, Kang KW, Kim JH, Jung KH. Unveiling the critical role of K + for xanthorhodopsin expression in E. coli. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 258:112976. [PMID: 39002191 DOI: 10.1016/j.jphotobiol.2024.112976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 06/19/2024] [Accepted: 07/01/2024] [Indexed: 07/15/2024]
Abstract
Xanthorhodopsin (XR), a retinal-binding 7-transmembrane protein isolated from the eubacterium Salinibacter ruber, utilizes two chromophores (retinal and salinixanthin (SAL)) as an outward proton pump and energy-donating carotenoid. However, research on XR has been impeded owing to limitations in achieving heterogeneous expression of stable forms and high production levels of both wild-type and mutants. We successfully expressed wild-type and mutant XRs in Escherichia coli in the presence of K+. Achieving XR expression requires significant K+ and a low inducer concentration. In particular, we highlight the significance of Ser-159 in helix E located near Gly-156 (a carotenoid-binding position) as a critical site for XR expression. Our findings indicate that replacing Ser-159 with a smaller amino acid, alanine, can enhance XR expression in a manner comparable to K+, implying that Ser-159 poses a steric hindrance for pigment formation in XR. In the presence of K+, the proton pumping and photocycle of the wild-type and mutants were characterized and compared; the wild-type result suggests similar properties to the first reported XR isolation from the S. ruber membrane fraction. We propose that the K+ gradient across the cell membrane of S. ruber serves to uphold the membrane potential of the organism and plays a role in the expression of proteins, such as XR, as demonstrated in our study. Our findings deepen the understanding of adaptive protein expression, particularly in halophilic organisms. We highlight salt selection as a promising strategy for improving protein yield and functionality.
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Affiliation(s)
- Chenda Hour
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kimleng Chuon
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Myung-Chul Song
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Jin-Gon Shim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Shin-Gyu Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea; Research Institute for Basic Science, Sogang University, Seoul, Republic of Korea
| | - Kun-Wook Kang
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Ji-Hyun Kim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, South Korea.
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Shim JG, Chuon K, Kim JH, Lee SJ, Song MC, Cho SG, Hour C, Jung KH. Proton-pumping photoreceptor controls expression of ABC transporter by regulating transcription factor through light. Commun Biol 2024; 7:789. [PMID: 38951607 PMCID: PMC11217422 DOI: 10.1038/s42003-024-06471-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 06/19/2024] [Indexed: 07/03/2024] Open
Abstract
Light is a significant factor for living organisms with photosystems, like microbial rhodopsin-a retinal protein that functions as an ion pump, channel, and sensory transduction. Gloeobacter violaceus PCC7421, has a proton-pumping rhodopsin gene, the Gloeobacter rhodopsin (GR). The helix-turn-helix family of transcriptional regulators has various motifs, and they regulate gene expression in the presence of various metal ions. Here, we report that active proton outward pumping rhodopsin interacted with the helix-turn-helix transcription regulator and regulated gene expression. This interaction is confirmed using ITC analysis (KD of 8 μM) and determined the charged residues required. During in vitro experiments using fluorescent and luciferase reporter systems, ATP-binding cassette (ABC) transporters and the self-regulation of G. violaceus transcriptional regulator (GvTcR) are regulated by light, and gene regulation is observed in G. violaceus using the real-time polymerase chain reaction. These results expand our understanding of the natural potential and limitations of microbial rhodopsin function.
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Affiliation(s)
- Jin-Gon Shim
- Department of Life Science, Sogang University, Seoul, South Korea
- Pharmacology Department, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kimleng Chuon
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Ji-Hyun Kim
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Sang-Ji Lee
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Myung-Chul Song
- Department of Life Science, Sogang University, Seoul, South Korea
- Research Institute for Basic Science, Sogang University, Seoul, Korea
| | - Shin-Gyu Cho
- Department of Life Science, Sogang University, Seoul, South Korea
- Research Institute for Basic Science, Sogang University, Seoul, Korea
| | - Chenda Hour
- Department of Life Science, Sogang University, Seoul, South Korea
| | - Kwang-Hwan Jung
- Department of Life Science, Sogang University, Seoul, South Korea.
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Tu W, Xu J, Thompson IP, Huang WE. Engineering artificial photosynthesis based on rhodopsin for CO 2 fixation. Nat Commun 2023; 14:8012. [PMID: 38049399 PMCID: PMC10696030 DOI: 10.1038/s41467-023-43524-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 11/11/2023] [Indexed: 12/06/2023] Open
Abstract
Microbial rhodopsin, a significant contributor to sustaining life through light harvesting, holds untapped potential for carbon fixation. Here, we construct an artificial photosynthesis system which combines the proton-pumping ability of rhodopsin with an extracellular electron uptake mechanism, establishing a pathway to drive photoelectrosynthetic CO2 fixation by Ralstonia eutropha (also known as Cupriavidus necator) H16, a facultatively chemolithoautotrophic soil bacterium. R. eutropha is engineered to heterologously express an extracellular electron transfer pathway of Shewanella oneidensis MR-1 and Gloeobacter rhodopsin (GR). Employing GR and the outer-membrane conduit MtrCAB from S. oneidensis, extracellular electrons and GR-driven proton motive force are integrated into R. eutropha's native electron transport chain (ETC). Inspired by natural photosynthesis, the photoelectrochemical system splits water to supply electrons to R. eutropha via the Mtr outer-membrane route. The light-activated proton pump - GR, supported by canthaxanthin as an antenna, powers ATP synthesis and reverses the ETC to regenerate NADH/NADPH, facilitating R. eutropha's biomass synthesis from CO2. Overexpression of a carbonic anhydrase further enhances CO2 fixation. This artificial photosynthesis system has the potential to advance the development of efficient photosynthesis, redefining our understanding of the ecological role of microbial rhodopsins in nature.
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Affiliation(s)
- Weiming Tu
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK
| | - Jiabao Xu
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK
| | - Ian P Thompson
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK
| | - Wei E Huang
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK.
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Petrovskaya LE, Lukashev EP, Lyukmanova EN, Shulepko MA, Kryukova EA, Ziganshin RH, Dolgikh DA, Maksimov EG, Rubin AB, Kirpichnikov MP, Lanyi JK, Balashov SP. Expression of Xanthorhodopsin in Escherichia coli. Protein J 2023:10.1007/s10930-023-10109-5. [DOI: 10.1007/s10930-023-10109-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2023] [Indexed: 04/03/2023]
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Ghosh M, Misra R, Bhattacharya S, Majhi K, Jung KH, Sheves M. Retinal-Carotenoid Interactions in a Sodium-Ion-Pumping Rhodopsin: Implications on Oligomerization and Thermal Stability. J Phys Chem B 2023; 127:2128-2137. [PMID: 36857147 PMCID: PMC10026069 DOI: 10.1021/acs.jpcb.2c07502] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Microbial rhodopsin (also called retinal protein)-carotenoid conjugates represent a unique class of light-harvesting (LH) complexes, but their specific interactions and LH properties are not completely elucidated as only few rhodopsins are known to bind carotenoids. Here, we report a natural sodium-ion (Na+)-pumping Nonlabens (Donghaeana) dokdonensis rhodopsin (DDR2) binding with a carotenoid salinixanthin (Sal) to form a thermally stable rhodopsin-carotenoid complex. Different spectroscopic studies were employed to monitor the retinal-carotenoid interaction as well as the thermal stability of the protein, while size-exclusion chromatography (SEC) and homology modeling are performed to understand the protein oligomerization process. In analogy with that of another Na+-pumping protein Krokinobacter eikastus rhodopsin 2 (KR2), we propose that DDR2 (studied concentration range: 2 × 10-6 to 4 × 10-5 M) remains mainly as a pentamer at room temperature and neutral pH, while heating above 55 °C partially converted it into a thermally less stable oligomeric form of the protein. This process is affected by both the pH and concentration. At high concentrations (4 × 10-5 to 2 × 10-4 M), the protein adopts a pentamer form reflected in the excitonic circular dichroism (CD) spectrum. In the presence of Sal, the thermal stability of DDR2 is increased significantly, and the pigment is stable even at 85 °C. The results presented could have implications in designing stable rhodopsin-carotenoid antenna complexes.
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Affiliation(s)
- Mihir Ghosh
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ramprasad Misra
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sudeshna Bhattacharya
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Koushik Majhi
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul 04107, South Korea
| | - Mordechai Sheves
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
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Cho SG, Song M, Chuon K, Shim JG, Meas S, Jung KH. Heliorhodopsin binds and regulates glutamine synthetase activity. PLoS Biol 2022; 20:e3001817. [PMID: 36190943 PMCID: PMC9529153 DOI: 10.1371/journal.pbio.3001817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 09/06/2022] [Indexed: 11/05/2022] Open
Abstract
Photoreceptors are light-sensitive proteins found in various organisms that respond to light and relay signals into the cells. Heliorhodopsin, a retinal-binding membrane protein, has been recently discovered, however its function remains unknown. Herein, we investigated the relationship between Actinobacteria bacterium IMCC26103 heliorhodopsin (AbHeR) and an adjacent glutamine synthetase (AbGS) in the same operon. We demonstrate that AbHeR binds to AbGS and regulates AbGS activity. More specifically, the dissociation constant (Kd) value of the binding between AbHeR and AbGS is 6.06 μM. Moreover, the absence of positively charged residues within the intracellular loop of AbHeR impacted Kd value as they serve as critical binding sites for AbGS. We also confirm that AbHeR up-regulates the biosynthetic enzyme activity of AbGS both in vitro and in vivo in the presence of light. GS is a key enzyme involved in nitrogen assimilation that catalyzes the conversion of glutamate and ammonia to glutamine. Hence, the interaction between AbHeR and AbGS may be critical for nitrogen assimilation in Actinobacteria bacterium IMCC26103 as it survives in low-nutrient environments. Overall, the findings of our study describe, for the first time, to the best of our knowledge, a novel function of heliorhodopsin as a regulatory rhodopsin with the capacity to bind and regulate enzyme activity required for nitrogen assimilation. A study of heliorhodopsin, an actinobacterial photoreceptor of unknown function, reveals that it interacts with glutamine synthetase, an enzyme involved in nitrogen assimilation, and regulates its activity in the presence of light, highlighting the diverse functions of rhodopsins in different organisms.
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Affiliation(s)
- Shin-Gyu Cho
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea,Research Institute for Basic Science, Sogang University, Seoul, Korea
| | - Myungchul Song
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea
| | - Kimleng Chuon
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea
| | - Jin-gon Shim
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea
| | - Seanghun Meas
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea,Department of Biology, Faculty of Science, Royal University of Phnom Penh, Phnom Penh, Cambodia
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Seoul, Korea,* E-mail:
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Shim J, Choun K, Kang K, Kim J, Cho S, Jung K. The binding of secondary chromophore for thermally stable rhodopsin makes more stable with temperature. Protein Sci 2022. [DOI: 10.1002/pro.4386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jin‐gon Shim
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kimleng Choun
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kun‐Wook Kang
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Ji‐Hyun Kim
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Shin‐Gyu Cho
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kwang‐Hwan Jung
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
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Carotenoid binding in Gloeobacteria rhodopsin provides insights into divergent evolution of xanthorhodopsin types. Commun Biol 2022; 5:512. [PMID: 35637261 PMCID: PMC9151804 DOI: 10.1038/s42003-022-03429-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 04/29/2022] [Indexed: 11/08/2022] Open
Abstract
The position of carotenoid in xanthorhodopsin has been elucidated. However, a challenging expression of this opsin and a complex biosynthesis carotenoid in the laboratory hold back the insightful study of this rhodopsin. Here, we demonstrated co-expression of the xanthorhodopsin type isolated from Gloeobacter violaceus PCC 7421-Gloeobacter rhodopsin (GR) with a biosynthesized keto-carotenoid (canthaxanthin) targeting the carotenoid binding site. Direct mutation-induced changes in carotenoid-rhodopsin interaction revealed three crucial features: (1) carotenoid locked motif (CLM), (2) carotenoid aligned motif (CAM), and color tuning serines (CTS). Our single mutation results at 178 position (G178W) confirmed inhibition of carotenoid binding; however, the mutants showed better stability and proton pumping, which was also observed in the case of carotenoid binding characteristics. These effects demonstrated an adaptation of microbial rhodopsin that diverges from carotenoid harboring, along with expression in the dinoflagellate Pyrocystis lunula rhodopsin and the evolutionary substitution model. The study highlights a critical position of the carotenoid binding site, which significantly allows another protein engineering approach in the microbial rhodopsin family.
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