Cryo-EM structure of the RC-LH core complex from an early branching photosynthetic prokaryote

Xin, Yueyong; Shi, Yang; Niu, Tongxin; Wang, Qingqiang; Niu, Wanqiang; Huang, Xiaojun; Ding, Wei; Yang, Lei; Blankenship, Robert E.; Xu, Xiaoling; Sun, Fei

doi:10.1038/s41467-018-03881-x

Cited by 60 publications

(82 citation statements)

References 53 publications

(100 reference statements)

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“…3HP bicycle fixes three CO 2 molecules and produces one pyruvate molecule with the consumption of seven ATP molecules and five molecules of reducing equivalents. A "chimeric" photosynthetic system is used to regenerate ATP and reducing equivalents (Xin et al, 2018).…”

Section: Natural Co 2 Fixation Pathwaysmentioning

confidence: 99%

Recent Advances in Developing Artificial Autotrophic Microorganism for Reinforcing CO2 Fixation

Liang

Zhao²,

Jian-ming

2020

Front. Microbiol.

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With the goal of achieving carbon sequestration, emission reduction and cleaner production, biological methods have been employed to convert carbon dioxide (CO2) into fuels and chemicals. However, natural autotrophic organisms are not suitable cell factories due to their poor carbon fixation efficiency and poor growth rate. Heterotrophic microorganisms are promising candidates, since they have been proven to be efficient biofuel and chemical production chassis. This review first briefly summarizes six naturally occurring CO2 fixation pathways, and then focuses on recent advances in artificially designing efficient CO2 fixation pathways. Moreover, this review discusses the transformation of heterotrophic microorganisms into hemiautotrophic microorganisms and delves further into fully autotrophic microorganisms (artificial autotrophy) by use of synthetic biological tools and strategies. Rapid developments in artificial autotrophy have laid a solid foundation for the development of efficient carbon fixation cell factories. Finally, this review highlights future directions toward large-scale applications. Artificial autotrophic microbial cell factories need further improvements in terms of CO2 fixation pathways, reducing power supply, compartmentalization and host selection.

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Section: Natural Co 2 Fixation Pathwaysmentioning

confidence: 99%

Recent Advances in Developing Artificial Autotrophic Microorganism for Reinforcing CO2 Fixation

Liang

Zhao²,

Jian-ming

2020

Front. Microbiol.

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“…A long-standing question is how the efficiency of the bacterial antenna can be so high at ambient temperature given that it is a partly disordered biological system. The structural data from atomic force 28,29 and cryo-electron microscopy 30 and functional results from two-dimensional electron spectroscopy and related calculations 31 clearly demonstrate the close packing of the BChl complexes and the strong coupling, respectively, which are the necessities for exciton formation. One can ask whether the funnelling of the excitation energy to the RC occurs through random hops or straight walks of the exciton?…”

Section: Discussionmentioning

confidence: 89%

Correlated clusters of closed reaction centers during induction of intact cells of photosynthetic bacteria

Maróti

Kovács

Kis

et al. 2020

Sci Rep

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Antenna systems serve to absorb light and to transmit excitation energy to the reaction center (Rc) in photosynthetic organisms. As the emitted (bacterio)chlorophyll fluorescence competes with the photochemical utilization of the excitation, the measured fluorescence yield is informed by the migration of the excitation in the antenna. In this work, the fluorescence yield concomitant with the oxidized dimer (p +) of the RC were measured during light excitation (induction) and relaxation (in the dark) for whole cells of photosynthetic bacterium Rhodobacter sphaeroides lacking cytochrome c 2 as natural electron donor to p + (mutant cycA). The relationship between the fluorescence yield and p + (fraction of closed RC) showed deviations from the standard Joliot-Lavergne-Trissl model: (1) the hyperbola is not symmetric and (2) exhibits hysteresis. These phenomena originate from the difference between the delays of fluorescence relative to P + kinetics during induction and relaxation, and in structural terms from the non-random distribution of the closed Rcs during induction. the experimental findings are supported by Monte Carlo simulations and by results from statistical physics based on random walk approximations of the excitation in the antenna. The applied mathematical treatment demonstrates the generalization of the standard theory and sets the stage for a more adequate description of the long-debated kinetics of fluorescence and of the delicate control and balance between efficient light harvest and photoprotection in photosynthetic organisms. Photosynthesis is responsible for the genesis, development and regulation of vast majority forms of life on the Earth by using the ultimate free energy source of the sun. The conversion of (sun)light to chemical energy is initiated by the absorption of the photons in the closely packed network of protein-pigment complexes (antenna) followed by funneling of the excitation energy (exciton) to a specially organized (B)Chl dimer (P) in the reaction centers (RC) 1. Here an electron is stripped from P (P→P +) converting the energy of the exciton into chemical (redox) energy of P/P +. The electron is transferred via the primary quinone acceptor Q A to the secondary quinone acceptor Q B producing a series of transient charge separated states (P + Q-). While Q A can accept one electron only, Q B performs two-electron chemistry: by binding two protons and forming reduced quinone QH 2 , it is exchanged for an oxidized quinone from the quinone pool in the membrane 2-4. To describe the functional cooperation of the antenna pigments in light collection, the loose concept of the photosynthetic unit (PSU) was introduced 5. According to the present knowledge, the structure of the PSU of photosynthetic bacteria can be identified as the core complex including the photochemical RC and the closely attached light-harvesting (core) antenna (LH1, B870 in Rhodobacter (Rba.) sphaeroides) together (if exists) with the peripheral antenna (LH2, B800-850 complex in Rba. sphaeroides) loosely arranged in ...

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“…viridis to 2.9 Å, pdb 6ET5 (Qian et al 2018 ) and the RC–LH Roseiflexus ( Rof. ) castenholzii to 4.1 Å, pdb 5YQ7 (Xin et al 2018 ).…”

Section: Introductionmentioning

confidence: 99%

A comparative look at structural variation among RC–LH1 ‘Core’ complexes present in anoxygenic phototrophic bacteria

2020

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All purple photosynthetic bacteria contain RC-LH1 'Core' complexes. The structure of this complex from Rhodobacter sphaeroides, Rhodopseudomonas palustris and Thermochromatium tepidum has been solved using X-ray crystallography. Recently, the application of single particle cryo-EM has revolutionised structural biology and the structure of the RC-LH1 'Core' complex from Blastochloris viridis has been solved using this technique, as well as the complex from the non-purple Chloroflexi species, Roseiflexus castenholzii. It is apparent that these structures are variations on a theme, although with a greater degree of structural diversity within them than previously thought. Furthermore, it has recently been discovered that the only phototrophic representative from the phylum Gemmatimonadetes, Gemmatimonas phototrophica, also contains a RC-LH1 'Core' complex. At present only a low-resolution EM-projection map exists but this shows that the Gemmatimonas phototrophica complex contains a double LH1 ring. This short review compares these different structures and looks at the functional significance of these variations from two main standpoints: energy transfer and quinone exchange.

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Cryo-EM structure of the RC-LH core complex from an early branching photosynthetic prokaryote

Cited by 60 publications

References 53 publications

Recent Advances in Developing Artificial Autotrophic Microorganism for Reinforcing CO2 Fixation

Recent Advances in Developing Artificial Autotrophic Microorganism for Reinforcing CO2 Fixation

Correlated clusters of closed reaction centers during induction of intact cells of photosynthetic bacteria

A comparative look at structural variation among RC–LH1 ‘Core’ complexes present in anoxygenic phototrophic bacteria

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