Structural insights into the coupling mechanism of vectorial CO₂ uptake by DAB1.
4 affiliations
- 1Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720.
- 2HHMI, University of California, Berkeley, CA 94720.
- 3Department of Physics, University of California, Berkeley, CA 94720.
- 4Innovative Genomics Institute, University of California, Berkeley, CA 94720.
Abstract
CO₂ transporters enable bacterial CO₂-concentrating mechanisms by catalyzing directional hydration of CO₂, yet the basis of this vectorial carbonic anhydrase (CA) activity remains an open question. We used cryoelectron microscopy to determine the structure of the DAB1 complex from Thermocrinis albus to 2.29 Å, revealing a heterotrimer in which a deeply buried β-CA active site in DabA is structurally coupled to the proton-translocating subunit DabB. Two conformational states define distinct solvent channels for substrate entry and product exit. A suppressor screen identifies mutations that disrupt coupling while retaining CA activity, underlying the importance of conserved residues that link proton translocation to active-site remodeling. These results support a model in which proton-driven conformational changes regulate substrate access to the active site, enabling vectorial CO₂ hydration.
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BibTeX
@article{phillips2026structural,
title = {{Structural insights into the coupling mechanism of vectorial CO₂ uptake by DAB1.}},
author = {Naiya R Phillips and Luke M Oltrogge and Jonathan P Remis and David F Savage},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2026},
month = oct,
doi = {10.1073/pnas.2616712123},
url = {https://europepmc.org/article/MED/42863049},
note = {CC BY},
}
RIS
TY - JOUR
TI - Structural insights into the coupling mechanism of vectorial CO₂ uptake by DAB1.
AU - Naiya R Phillips
AU - Luke M Oltrogge
AU - Jonathan P Remis
AU - David F Savage
PY - 2026
DA - 2026/10/12
JO - Proceedings of the National Academy of Sciences of the United States of America
DO - 10.1073/pnas.2616712123
UR - https://europepmc.org/article/MED/42863049
AB - CO₂ transporters enable bacterial CO₂-concentrating mechanisms by catalyzing directional hydration of CO₂, yet the basis of this vectorial carbonic anhydrase (CA) activity remains an open question. We used cryoelectron microscopy to determine the structure of the DAB1 complex from Thermocrinis albus to 2.29 Å, revealing a heterotrimer in which a deeply buried β-CA active site in DabA is structurally coupled to the proton-translocating subunit DabB. Two conformational states define distinct solvent channels for substrate entry and product exit. A suppressor screen identifies mutations that disrupt coupling while retaining CA activity, underlying the importance of conserved residues that link proton translocation to active-site remodeling. These results support a model in which proton-driven conformational changes regulate substrate access to the active site, enabling vectorial CO₂ hydration.
SN - 0027-8424
SN - 1091-6490
ER -