Dissolved Inorganic Carbon-Accumulating Complexes from Autotrophic Bacteria from Extreme Environments

Authors

Sarah Schmid, University of South Florida
Dale Chaput, University of South FloridaFollow
Mya Breitbart, University of South FloridaFollow
Rebecca Hines, University of South Florida
Samantha Williams, University of South Florida
Hunter K. Gossett, University of South Florida
Sheila D. Parsi, University of South Florida
Rebecca Peterson, University of South Florida
Robert A. Whittaker, University of South Florida
Angela Tarver, U.S. Department of Energy Joint Genome Institute, Berkeley
Kathleen M. Scott, University of South FloridaFollow

Document Type

Article

Publication Date

2021

Keywords

autotroph, carbon dioxide, carbon dioxide-concentrating mechanism, carbon fixation, dissolved inorganic carbon

Digital Object Identifier (DOI)

https://doi.org/https://doi.org/10.1128/JB.00377-21

Abstract

In nature, concentrations of dissolved inorganic carbon (DIC; CO₂ + HCO₃⁻ + CO₃²⁻) can be low, and autotrophic organisms adapt with a variety of mechanisms to elevate intracellular DIC concentrations to enhance CO₂ fixation. Such mechanisms have been well studied in Cyanobacteria, but much remains to be learned about their activity in other phyla. Novel multisubunit membrane-spanning complexes capable of elevating intracellular DIC were recently described in three species of bacteria. Homologs of these complexes are distributed among 17 phyla in Bacteria and Archaea and are predicted to consist of one, two, or three subunits. To determine whether DIC accumulation is a shared feature of these diverse complexes, seven of them, representative of organisms from four phyla, from a variety of habitats, and with three different subunit configurations, were chosen for study. A high-CO₂-requiring, carbonic anhydrase-deficient (ΔyadF ΔcynT) strain of Escherichia coli Lemo21(DE3), which could be rescued via elevated intracellular DIC concentrations, was created for heterologous expression and characterization of the complexes. Expression of all seven complexes rescued the ability of E. coli Lemo21(DE3) ΔyadF ΔcynT to grow under low-CO₂ conditions, and six of the seven generated measurably elevated intracellular DIC concentrations when their expression was induced. For complexes consisting of two or three subunits, all subunits were necessary for DIC accumulation. Isotopic disequilibrium experiments clarified that CO₂ was the substrate for these complexes. In addition, the presence of an ionophore prevented the accumulation of intracellular DIC, suggesting that these complexes may couple proton potential to DIC accumulation.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Journal of Bacteriology, v. 203, no. 23

Scholar Commons Citation

Schmid, Sarah; Chaput, Dale; Breitbart, Mya; Hines, Rebecca; Williams, Samantha; Gossett, Hunter K.; Parsi, Sheila D.; Peterson, Rebecca; Whittaker, Robert A.; Tarver, Angela; and Scott, Kathleen M., "Dissolved Inorganic Carbon-Accumulating Complexes from Autotrophic Bacteria from Extreme Environments" (2021). Marine Science Faculty Publications. 2582.
https://digitalcommons.usf.edu/msc_facpub/2582