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DOE OSTI · 1841957

Photosynthesis | The Heliobacteria

Orf, Gregory S.·Redding, Kevin E.
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Abstract

The heliobacteria are the only phototrophs in the Gram-positive group of bacteria. They are strict anaerobes that grow in a primarily fermentative mode in the dark. In the light, they use a homodimeric Type I photochemical reaction center to drive cyclic electron transport. They are unique in using the pigment bacteriochlorophyll g. All heliobacteria are unable to fix CO 2 but able to fix N2. Their core metabolism includes a complete TCA cycle with several reversible enzymes in common with the reverse (reductive) TCA cycle, but they lack an (ATP) citrate lyase that would allow CO 2 fixation. There are now several sequenced genomes available for different heliobacterial species, allowing hypotheses to be made concerning their metabolic potential. Here, techniques to introduce replicating plasmids into Heliobacterium modesticaldum, as well as leveraging its endogenous CRISPR/Cas system to edit its chromosome, have recently been pioneered, contributing to making this species a model system for this family.

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59 BASIC BIOLOGICAL SCIENCESClostridialesCRISPR-CasCyclic electron flowFirmicutesHeliobacteriaNitrogen fixationOxygenic photosynthesisPhototrophyReaction center

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Orf, Gregory S., Redding, Kevin E.. 2021-08-02. Photosynthesis | The Heliobacteria. https://doi.org/10.1016/b978-0-12-819460-7.00220-6

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