Related Experiment Video
Updated: Jan 12, 2026
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
10:01
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
12.6K
Engineering O2-Tolerant Chimeric Hydrogenases Optimized for Ferredoxin Coupling in Synechocystis sp. PCC 6803.
Elisabeth Lettau1,2, Jacky Till3,4, Jörg Toepel3
1RWTH Aachen University, iAMB-Institute of Applied Microbiology, Worringerweg 1, 52074 Aachen, Germany.
ACS Synthetic Biology
|November 7, 2025
Summary
Researchers engineered chimeric [NiFe]-hydrogenases by combining oxygen-tolerant and ferredoxin-interacting enzymes. This modular approach advances sustainable biohydrogen production by improving oxygen tolerance and ferredoxin interaction for photosynthesis-coupled hydrogen generation.
Area of Science:
- Biotechnology and Bioengineering
- Enzyme Engineering
- Sustainable Energy
Background:
- Developing efficient hydrogenases for biohydrogen production is crucial for sustainable energy.
- Existing hydrogenases often struggle with oxygen sensitivity or inefficient ferredoxin interaction.
- Oxygenic photosynthesis presents a challenge for integrating hydrogenase activity.
Purpose of the Study:
- To engineer chimeric NAD+-reducing [NiFe]-hydrogenases (SH) with enhanced oxygen tolerance and ferredoxin interaction.
- To combine structural elements from oxygen-tolerant *Cupriavidus necator* SH (*Cn*SH) and ferredoxin-interacting *Synechocystis* sp. PCC6803 SH (*Syn*SH).
- To create functional hydrogenase modules for potential photosynthesis-coupled biohydrogen production.
Main Methods:
- Constructed chimeric hydrogenases (MixSH, Ch-HoxEFSyn+UCn, Ch-HoxUswapCTD) by engineering HoxU and HoxF subunits.
- Tested oxygen tolerance via lithoautotrophic growth of *C. necator*.
- Assessed hydrogenase activity, including H2 consumption and production, in *Synechocystis*.
Main Results:
- Engineered chimeric hydrogenases successfully coupled *Cn*HoxYH and *Syn*HoxEFU modules, retaining oxygen tolerance.
- Demonstrated partial hydrogenase function in *Synechocystis*, including H2 consumption and fermentative H2 production.
- Identified a functional ferredoxin-binding site in HoxF and showed structural analogy between *Cn*HoxF and *Syn*HoxE.
Conclusions:
- Modular engineering of [NiFe]-hydrogenases can unite oxygen tolerance with ferredoxin interaction.
- This study provides a foundational step toward developing hydrogenases for photosynthesis-coupled biohydrogen production.
- Further optimization is needed to improve electron transfer efficiency and overall activity in photosynthetic organisms.
Related Concept Videos
01:30Anoxygenic Photosynthesis
1.1K
Anoxygenic photosynthesis is a phototrophic process that captures light energy to drive carbon fixation without producing molecular oxygen. Unlike oxygenic photosynthesis, which utilizes water as an electron donor and releases oxygen, anoxygenic phototrophs use alternative electron donors such as hydrogen sulfide (H₂S), elemental sulfur (S⁰), or thiosulfate (S₂O₃²⁻). This process is carried out by diverse groups of bacteria, including purple bacteria, green...
1.1K
01:15Metabolism of Chemolithotrophs
741
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
741
01:32Chemiosmosis
112.0K
Oxidative phosphorylation is a highly efficient process that generates large amounts of adenosine triphosphate (ATP), the basic unit of energy that drives many cellular processes. Oxidative phosphorylation involves two processes— the electron transport chain and chemiosmosis.
Electron Transport Chain
The electron transport chain involves a series of protein complexes on the inner mitochondrial membrane that undergo a series of redox reactions. At the end of this chain, the electrons...
Electron Transport Chain
The electron transport chain involves a series of protein complexes on the inner mitochondrial membrane that undergo a series of redox reactions. At the end of this chain, the electrons...
112.0K
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.8K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.8K
01:43Electron Transport Chain: Complex III and IV
9.0K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
9.0K
01:28Carbon-dioxide Fixation
610
Carbon dioxide fixation in prokaryotes enables the assimilation of inorganic carbon into organic molecules, supporting biosynthetic pathways, sustaining ecosystems, and contributing to the global carbon cycle. It also has industrial applications in carbon capture and bioproduct synthesis. Autotrophic organisms rely on this process to utilize CO₂ as a carbon source in diverse environments.The Calvin CycleThe Calvin cycle is the most widespread carbon fixation mechanism, primarily used by...
610