PXD076189-1

PXD076189 is an original dataset announced via ProteomeXchange.

Title	Structural Basis of Membrane Potential Coupled Vectorial CO₂ Hydration by the DAB2 Complex in Chemolithoautotrophs
Description	The fixation of dissolved inorganic carbon (DIC) such as CO2 and bicarbonate is fundamental to the global primary production. Many autotrophs depend on a diversity of CO2-concentrating mechanisms (CCMs) to overcome the inefficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase and the limited supply of DIC. While cyanobacterial CCMs are well characterized, analogous systems in chemolithoautotrophs, specifically active DIC uptake systems have long been overlooked. Here, we present the first cryo-EM analysis of DAB2, an essential membrane-associated complex for CO₂ uptake in Halothiobacillus neapolitanus. The cytoplasmic subunit DabA2 displays a β-carbonic anhydrase-like fold, while the transmembrane subunit DabB2 resembles the proton-conducting subunits of respiratory Complex I. Purified DAB2 binds CO₂ independent of proton motive force (PMF) however, did not spontaneously hydrate CO2. Structural analysis reveals a deeply buried active site only accessible via gated substrate tunnels, suggesting substrate access and catalysis are tightly regulated. The transmembrane helix of DabA2 forms the proton pathway and potentially couples proton translocation to the catalysis. These features define a vectorial CO2 hydration mechanism that prohibits reverse bicarbonate dehydration. Our findings establish DAB2 as a prototype of a previously unrecognized family of PMF-driven carbonic anhydrases, elucidating a novel strategy for CO₂ capture in non-photosynthetic autotrophs.
HostingRepository	PRIDE
AnnounceDate	2026-04-17
AnnouncementXML	Submission_2026-04-17_06:40:53.158.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Timo Glatter
SpeciesList	scientific name: Escherichia coli; NCBI TaxID: NEWT:562;
ModificationList	No PTMs are included in the dataset
Instrument	Q Exactive HF

Revision	Datetime	Status	ChangeLog Entry
0	2026-03-26 06:21:30	ID requested
⏵ 1	2026-04-17 06:40:53	announced

Dataset with its publication pending

submitter keyword: Halothiobacillus neapolitanus,CO2

Timo Glatter
contact affiliation	Max Planck Institute for Terrestrial Microbiology Karl-von-Frisch Str. 10 35043 Marburg Germany
contact email	timo.glatter@mpi-marburg.mpg.de
lab head
Timo Glatter
contact affiliation	Max Planck Institute for Terrestrial Microbiology Marburg
contact email	timo.glatter@mpi-marburg.mpg.de
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD076189
     1. Label: PRIDE project
     2. Name: Structural Basis of Membrane Potential Coupled Vectorial CO₂ Hydration by the DAB2 Complex in Chemolithoautotrophs