Bacterial choline-O-sulfate uptake and desulfation

A bacterial uptake-and-hydrolysis mechanism in which intact choline-O-sulfate enters the cell and is cleaved by BetC to choline, sulfate and a proton. Import implementations and molecular assignments vary among lineages. Uptake for osmoprotection without hydrolysis is a distinct outcome; downstream choline oxidation and sulfur assimilation lie outside this boundary.

MODULE:bacterial_choline_o_sulfate_uptake_and_desulfationCOMPLETEABSTRACTMetabolic Pathwaymodules/bacterial_choline_o_sulfate_uptake_and_desulfation.yaml
choline-O-sulfate utilization
PMID:17116241
Uncoupling of choline-O-sulphate utilization from osmoprotection in Pseudomonas putida.
A KT2440 betC deletion retained choline-O-sulfate accumulation but lost its use as a carbon or nitrogen source. This supports BetC in utilization while showing that uptake is BetC-independent; it does not establish the adjacent BetD/BetE candidates as an importer.
This mutant still accumulated intact COS but failed to use this compound as carbon or nitrogen source.
PMID:9736747
Presence of a gene encoding choline sulfatase in Sinorhizobium meliloti bet operon: choline-O-sulfate is metabolized into glycine betaine.
Sinorhizobium genetics and enzyme assays establish BetC as a choline sulfatase that converts choline-O-sulfate to choline.
a new gene (betC) was identified as encoding a choline sulfatase catalyzing the conversion of choline-O-sulfate and, at a lower rate, phosphorylcholine, into choline.
PMID:29458126
Structural and Mechanistic Analysis of the Choline Sulfatase from Sinorhizobium melliloti: A Class I Sulfatase Specific for an Alkyl Sulfate Ester.
Purified Sinorhizobium BetC efficiently hydrolyzes choline-O-sulfate, and its crystal structure defines the choline-sulfatase catalytic exemplar.
Sinorhizobium meliloti choline sulfatase (SmCS) efficiently catalyzes the hydrolysis of alkyl sulfate choline-O-sulfate
PMID:23354714
Homeostasis and catabolism of choline and glycine betaine: lessons from Pseudomonas aeruginosa.
Comparative review: osmoprotectant accumulation and nutrient catabolism are different fates. Choline-to-betaine conversion and further catabolism remain outside the uptake/desulfation boundary.
the GB intermediate represents a metabolic decision point to determine whether GB is catabolized or stored as an osmo- and stress protectant.
PMID:10717312
Riding the sulfur cycle--metabolism of sulfonates and sulfate esters in gram-negative bacteria.
Comparative review distinguishes sulfur acquisition from carbon-skeleton catabolism. COS hydrolysis does not by itself establish every downstream physiological use.
Many microorganisms can use sulfonates and sulfate esters as a source of sulfur for growth
PMID:11421275
Bacterial transporters for sulfate and organosulfur compounds.
Historical transporter review distinguishes uptake machinery from intracellular metabolism. Its 2001 ABC survey is not evidence that an unresolved SulP candidate carries COS.
the sulfonate and sulfate ester transporters identified to date are all ABC-type systems
PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
OpuC directly imports COS, but the assayed Bacillus strains accumulate it intact rather than hydrolyzing it; this is a transport exemplar, not a complete native pathway exemplar.
choline-O-sulfate was specifically acquired from the environment via OpuC.
PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
Uptake is insufficient to establish this two-step module: COS remains a metabolically inert compatible solute in the assayed Bacillus strains.
PMID:26058574
Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade.
The native DSS-3 betC mutant supports COS utilization through SPO1083; the BetT COS-growth phenotype is partial and does not identify a directly measured COS uptake reaction.
Growth of the ΔbetT::Gm mutant on COS (μ = 0.027 ± 0.001 h−1) was also affected

Bacteria is the reusable scope, not a universal distribution claim. OpuC supplies a resolved transport exemplar from Bacillus, whose tested strains do not perform the complete hydrolytic pathway. Pseudomonas, Sinorhizobium and Ruegeria provide physiological or biochemical hydrolysis evidence, while their COS importer assignments remain open. BetD/BetE and BetT candidates are not mandatory core components. BetC uses the specific TIGR03417/IPR017785 lineage rather than the heterogeneous PTHR45953 family. OpuC subunit family assignments are classification evidence, not cargo predictions; related OpuB proteins cannot substitute merely because a family label matches. Whole-cell observed uptake and gene-based capacity are separate evidence modes. No native compatibility of components taken from different taxa is implied. Ruegeria is a hydrolysis/utilization comparator with unresolved compartment; its growth phenotype does not count as directly observed intact COS uptake. The four OpuC components are distinct subunit types, not a four-polypeptide stoichiometry. For ontology maintenance, no exact COS-transporter GO term was identified. Generic transmembrane transport with structured COS cargo represents the measured complex activity; subunit contributions remain distinct from independently enabled transport. A term request would improve terminology, without constituting an unresolved biological activity.

8Nodes
5Parts
1Variant Sets
2Variants
6Annotons
1Connections

Derived QC

Recommended-field compliance

84.6% recommended fields populated
  • references[8] · findings (0/1)
  • references[10] · findings (0/1)

Module deep research

✓ present

  • bacterial_choline_o_sulfate_uptake_and_desulfation-deep-research-openscientist.md (openscientist)

Leaf nodes lacking representative members

✓ representative grounding skipped for abstract module.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

5 gene-function check(s) reflected in core functions · 0 conflict(s) · 4 evidence or coverage gap(s) (12 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
opuc_cos_transport PROTEIN_COMPLEX
Gene 		transmembrane transporter activity
GO:0022857 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
unresolved_cos_import_activity ANY_WITH_FUNCTION
Gene 		transmembrane transporter activity
GO:0022857 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.
betc_choline_sulfatase_activity betC (Pseudomonas putida KT2440)
UniProtKB:Q88RQ2
Family Representative 		choline-sulfatase activity
GO:0047753 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
betc_choline_sulfatase_activity betC (Sinorhizobium meliloti 1021; experimentally characterized SmCS)
UniProtKB:O69787
Family Representative 		choline-sulfatase activity
GO:0047753 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
betc_choline_sulfatase_activity betC-1 (RUEPO)
UniProtKB:Q5LUH1
Family Representative 		choline-sulfatase activity
GO:0047753 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
bete_transport_candidate PP_0075 (Pseudomonas putida KT2440; BetE candidate)
UniProtKB:Q88RQ4
Family Representative 		transmembrane transporter activity
GO:0022857 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
betd_binding_candidate PP_0076 (Pseudomonas putida KT2440; BetD candidate)
UniProtKB:Q88RQ3
Family Representative 		quaternary ammonium group binding
GO:0050997 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
ruegeria_bett_candidate SPO1087 (RUEPO)
UniProtKB:Q5LUG7
Family Representative 		transmembrane transporter activity
No function ID 		No Function Id
A gene review exists, but this function lacks a GO identifier. Free-text chemistry is not automatically compared.
betc_choline_sulfatase_activity BetC choline-sulfatase family (InterPro IPR017785)
NCBIfam:TIGR03417
Family 		choline-sulfatase activity
GO:0047753 		Family Review Missing
No supported structured family review is available for NCBIfam:TIGR03417.
bete_transport_candidate PANTHER PTHR11814 SLC26/SulP transporter family
PANTHER:PTHR11814
Family 		transmembrane transporter activity
GO:0022857 		Family Supported
Family review supports GO:0022857 FAMILY_WIDE. Generic transmembrane transporter activity is the root PAINT assertion (PTN002483418, assessed SOUND), seeded from bacteria to mammals, and every member carries the SLC26/SulP multipass transport domain. Only the generic activity is family-wide: cargo (sulfate, chloride, bicarbonate, oxalate, C4-dicarboxylates) and coupling are clade-specific, and mammalian prestin is specialized as a membrane motor. For bacterial members such as P. putida PP_0075 nothing more specific than this term is inherited.
betd_binding_candidate choline-transporter substrate-binding family (InterPro IPR017783)
NCBIfam:TIGR03414
Family 		quaternary ammonium group binding
GO:0050997 		Family Review Missing
No supported structured family review is available for NCBIfam:TIGR03414.
ruegeria_bett_candidate Ruegeria BetT-type membrane transport proteins with verified locus identity
Family 		transmembrane transporter activity
No function ID 		No Function Id
The family function has no GO identifier for comparison; prose is not matched.

Gene-review completeness (10/10 grounded genes reviewed)

7 complete review(s) · 4 with deep research · 0 missing review · 6 reviewed but lacking deep research

Gene Review Complete Deep research
betC O69787 ✓ 3/4 ✓
betC Q88RQ2 ✓ 2/3 ✓
betC-1 Q5LUH1 ✓ 2/3 ✗
opuCA O34992 ✓ ✓ ✗
opuCB O34878 ✓ ✓ ✗
opuCC O32243 ✓ ✓ ✗
opuCD O34742 ✓ ✓ ✗
PP_0075 Q88RQ4 ✓ ✓ ✓
PP_0076 Q88RQ3 ✓ ✓ ✓
SPO1087 Q5LUG7 ✓ ✓ ✗

Details

Context
bacteriaNCBITaxon:2
Bacterial choline-O-sulfate uptake and desulfationMetabolic Pathwaybacterial_choline_o_sulfate_uptake_and_desulfation
choline-O-sulfate utilization
Context
bacteriaNCBITaxon:2

Connections

Intact intracellular COS supplied by an uptake route is hydrolyzed by BetC. This order is established for the defined module boundary, but a utilization phenotype alone does not establish the compartment or order in every lineage.
PMID:17116241
Uncoupling of choline-O-sulphate utilization from osmoprotection in Pseudomonas putida.
A KT2440 betC deletion retained choline-O-sulfate accumulation but lost its use as a carbon or nitrogen source. This supports BetC in utilization while showing that uptake is BetC-independent; it does not establish the adjacent BetD/BetE candidates as an importer.
This mutant still accumulated intact COS but failed to use this compound as carbon or nitrogen source.
PMID:9736747
Presence of a gene encoding choline sulfatase in Sinorhizobium meliloti bet operon: choline-O-sulfate is metabolized into glycine betaine.
Sinorhizobium genetics and enzyme assays establish BetC as a choline sulfatase that converts choline-O-sulfate to choline.
a new gene (betC) was identified as encoding a choline sulfatase catalyzing the conversion of choline-O-sulfate and, at a lower rate, phosphorylcholine, into choline.
Part 1: intact COS import
Intact choline-O-sulfate importTransport Stepcholine_o_sulfate_import
PMID:11421275
Bacterial transporters for sulfate and organosulfur compounds.
Historical transporter review distinguishes uptake machinery from intracellular metabolism. Its 2001 ABC survey is not evidence that an unresolved SulP candidate carries COS.
the sulfonate and sulfate ester transporters identified to date are all ABC-type systems
PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
OpuC directly imports COS, but the assayed Bacillus strains accumulate it intact rather than hydrolyzing it; this is a transport exemplar, not a complete native pathway exemplar.
choline-O-sulfate was specifically acquired from the environment via OpuC.
PMID:17116241
Uncoupling of choline-O-sulphate utilization from osmoprotection in Pseudomonas putida.
A KT2440 betC deletion retained choline-O-sulfate accumulation but lost its use as a carbon or nitrogen source. This supports BetC in utilization while showing that uptake is BetC-independent; it does not establish the adjacent BetD/BetE candidates as an importer.
This mutant still accumulated intact COS but failed to use this compound as carbon or nitrogen source.
Variant set: cos_import_realizer_axis (One Or More)
OpuC-mediated COS importTransport Stepopuc_choline_o_sulfate_import

A characterized uptake implementation. Bacillus OpuC is an import-only exemplar at this boundary: the native assayed strain does not hydrolyze COS.

PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
OpuC directly imports COS, but the assayed Bacillus strains accumulate it intact rather than hydrolyzing it; this is a transport exemplar, not a complete native pathway exemplar.
choline-O-sulfate was specifically acquired from the environment via OpuC.
PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
Uptake is insufficient to establish this two-step module: COS remains a metabolically inert compatible solute in the assayed Bacillus strains.

Annotons

Assembled OpuC COS transport
opuc_cos_transport
Participant: Protein Complex: OpuC compatible-solute ABC importer
Protein Complex:
OpuC compatible-solute ABC importer
Active units:
opuCA OpuC subunit
Participant: Family: opuCA role within an experimentally supported OpuC complex
Family:
opuCA role within an experimentally supported OpuC complexPANTHER:PTHR43117:SF3 The classification contains related transport-system proteins. Independent OpuC role and assembled-complex cargo evidence are required; the official family label alone does not specify COS.
Representative Members: opuCA (BACSU)UniProtKB:O34992
Role: ATP-coupling subunit; family membership or ATPase activity alone does not establish COS transport.
opuCB OpuC subunit
Participant: Family: opuCB role within an experimentally supported OpuC complex
Family:
opuCB role within an experimentally supported OpuC complexPANTHER:PTHR30177:SF28 The classification contains related transport-system proteins. Independent OpuC role and assembled-complex cargo evidence are required; the official family label alone does not specify COS.
Representative Members: opuCB (BACSU)UniProtKB:O34878
Role: First membrane subunit of the OpuC transporter; requires the other OpuC components.
opuCC OpuC subunit
Participant: Family: opuCC role within an experimentally supported OpuC complex
Family:
opuCC role within an experimentally supported OpuC complexPANTHER:PTHR30024:SF44 The classification contains related transport-system proteins. Independent OpuC role and assembled-complex cargo evidence are required; the official family label alone does not specify COS.
Representative Members: opuCC (BACSU)UniProtKB:O32243
Role: Lipid-anchored substrate-binding subunit. The COS range is demonstrated for the assembled transporter, not inferred from the family label.
opuCD OpuC subunit
Participant: Family: opuCD role within an experimentally supported OpuC complex
Family:
opuCD role within an experimentally supported OpuC complexPANTHER:PTHR30177:SF4 The classification contains related transport-system proteins. Independent OpuC role and assembled-complex cargo evidence are required; the official family label alone does not specify COS.
Representative Members: opuCD (BACSU)UniProtKB:O34742
Role: Second membrane subunit of the OpuC transporter; a related OpuB/other permease is not automatically an OpuC realizer.

Function

transmembrane transporter activityGO:0022857
Cargo: choline sulfateCHEBI:16822

Imports intact COS using the assembled ABC system with four distinct subunit types (including two OpuCA copies). Every subunit contributes to transport; none is asserted to enable this activity alone.

PMID:9925583
High-affinity transport of choline-O-sulfate and its use as a compatible solute in Bacillus subtilis.
OpuC directly imports COS, but the assayed Bacillus strains accumulate it intact rather than hydrolyzing it; this is a transport exemplar, not a complete native pathway exemplar.
choline-O-sulfate was specifically acquired from the environment via OpuC.
PMID:10216873
Two evolutionarily closely related ABC transporters mediate the uptake of choline for synthesis of the osmoprotectant glycine betaine in Bacillus subtilis.
OpuC has distinct ATP-coupling, substrate-binding and two membrane-subunit roles. This architecture is required together with whole-complex COS uptake evidence; related-family proteins alone are insufficient.

Family/domain matches must be combined with curated OpuC subunit roles and complex-level COS cargo evidence. Do not infer a native Bacillus desulfation pathway.

Observed COS import with unresolved molecular identityTransport Stepunresolved_choline_o_sulfate_import

Retains the required import role where whole-cell physiology establishes intracellular COS supply but cannot assign a specific transporter. A missing gene assignment is an abduction target, not evidence that uptake is absent.

The production Boolean compiler leaves cargo and molecular-assignment constraints to the oracle. A gene-only inventory may leave this role unresolved even when native pathway physiology is established.

Annotons

Unassigned COS import activity
unresolved_cos_import_activity
Participant: Any With Function: transmembrane transporter activity
Required Function:
transmembrane transporter activityGO:0022857
Cargo: choline sulfateCHEBI:16822
No molecular family or representative is asserted until the cargo-specific importer is identified. Generic transporter activity alone cannot fill this role.

Function

transmembrane transporter activityGO:0022857
Cargo: choline sulfateCHEBI:16822

Supplies intact intracellular COS to BetC. KT2440 intact-accumulation evidence can establish this role without identifying its gene. Ruegeria COS growth alone cannot: hydrolysis compartment and intact uptake remain unresolved.

PMID:17116241
Uncoupling of choline-O-sulphate utilization from osmoprotection in Pseudomonas putida.
A KT2440 betC deletion retained choline-O-sulfate accumulation but lost its use as a carbon or nitrogen source. This supports BetC in utilization while showing that uptake is BetC-independent; it does not establish the adjacent BetD/BetE candidates as an importer.
This mutant still accumulated intact COS but failed to use this compound as carbon or nitrogen source.
Part 2: choline-O-sulfate hydrolysis
BetC choline-O-sulfate hydrolysisReactionbetc_choline_o_sulfate_hydrolysis

Annotons

BetC choline-sulfatase activity
betc_choline_sulfatase_activity
Participant: Family: BetC choline-sulfatase family (InterPro IPR017785)
Family:
BetC choline-sulfatase family (InterPro IPR017785)NCBIfam:TIGR03417 TIGR03417 and IPR017785 distinguish the choline-sulfatase lineage from the heterogeneous PANTHER sulfatase family. Named exemplars also have physiological or biochemical support. Sequence classification alone does not establish identical kinetic profiles or every promiscuous substrate.
Representative Members: betC (Pseudomonas putida KT2440)UniProtKB:Q88RQ2 betC (Sinorhizobium meliloti 1021; experimentally characterized SmCS)UniProtKB:O69787 betC-1 (RUEPO)UniProtKB:Q5LUH1

Function

choline-sulfatase activityGO:0047753
Substrates: choline-O-sulfateCHEBI:16822 waterCHEBI:15377
Products: cholineCHEBI:15354 sulfateCHEBI:16189 protonCHEBI:15378

Cleaves the sulfate ester, releasing choline for downstream metabolism and sulfate for cellular use or excretion.

PMID:9736747
Presence of a gene encoding choline sulfatase in Sinorhizobium meliloti bet operon: choline-O-sulfate is metabolized into glycine betaine.
Sinorhizobium genetics and enzyme assays establish BetC as a choline sulfatase that converts choline-O-sulfate to choline.
a new gene (betC) was identified as encoding a choline sulfatase catalyzing the conversion of choline-O-sulfate and, at a lower rate, phosphorylcholine, into choline.
PMID:29458126
Structural and Mechanistic Analysis of the Choline Sulfatase from Sinorhizobium melliloti: A Class I Sulfatase Specific for an Alkyl Sulfate Ester.
Purified Sinorhizobium BetC efficiently hydrolyzes choline-O-sulfate, and its crystal structure defines the choline-sulfatase catalytic exemplar.
Sinorhizobium meliloti choline sulfatase (SmCS) efficiently catalyzes the hydrolysis of alkyl sulfate choline-O-sulfate
PMID:26058574
Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade.
The native DSS-3 betC mutant supports COS utilization through SPO1083; the BetT COS-growth phenotype is partial and does not identify a directly measured COS uptake reaction.
Growth of the ΔbetT::Gm mutant on COS (μ = 0.027 ± 0.001 h−1) was also affected
PMID:35503214
Structural insights into choline-O-sulfatase reveal the molecular determinants for ligand binding.
Ligand-bound CECT 4857 BetC structures support hydrolysis-product recognition in this family. They are homolog evidence for the 1021 exemplar and revise the earlier binding-site interpretation, not an additional assay of O69787.
The binding mode of this AP superfamily member to both products of the reaction (sulfate and choline)

The 2018 recombinant Sinorhizobium experiment used 1021/O69787. The 2022 ligand structures used CECT 4857/MH208481 and are homolog evidence unless explicitly sequence-mapped. Ruegeria SPO1083 has native COS-utilization evidence; no purified Ruegeria enzyme assay is claimed. No common cellular location is asserted across all exemplars: native BetC compartments are unresolved, so hydrolysis evidence alone does not resolve the compartment or transport order. KT2440 intact-COS accumulation is positive evidence for import, without a localization assay for its BetC.

Part: qualified transporter-locus candidate (optional)
BetE SLC26A/SulP transport candidateTransport Stepbete_transport_candidate_context

Candidate context only; this role does not satisfy the required cargo-specific COS import step.

Annotons

BetE SLC26A/SulP transport candidate
bete_transport_candidate
Participant: Family: PANTHER PTHR11814 SLC26/SulP transporter family
Family:
PANTHER PTHR11814 SLC26/SulP transporter familyPANTHER:PTHR11814 PANTHER PTHR11814 is a heterogeneous SLC26/SulP family whose bacterial members carry C4-dicarboxylate, bicarbonate or unknown cargo; the family name does not establish sulfate or choline-O-sulfate transport for this candidate.
Representative Members: PP_0075 (Pseudomonas putida KT2440; BetE candidate)UniProtKB:Q88RQ4

Function

transmembrane transporter activityGO:0022857

Processes

transmembrane transportGO:0055085

Locations

plasma membraneGO:0005886

Multi-pass transport candidate adjacent to betC. Its transported substrate and coupling mechanism are not established.

Part: qualified transporter-locus candidate (optional)
BetD periplasmic binding-protein candidateTransport Stepbetd_binding_candidate_context

Candidate context only; this role does not satisfy the required cargo-specific COS import step.

Annotons

BetD periplasmic binding-protein candidate
betd_binding_candidate
Participant: Family: choline-transporter substrate-binding family (InterPro IPR017783)
Family:
choline-transporter substrate-binding family (InterPro IPR017783)NCBIfam:TIGR03414 Family assignment supports binding of a choline-related ligand, but the physiological ligand and transport partner are unresolved.
Representative Members: PP_0076 (Pseudomonas putida KT2440; BetD candidate)UniProtKB:Q88RQ3

Function

quaternary ammonium group bindingGO:0050997

Processes

transmembrane transportGO:0055085 quaternary ammonium group transportGO:0015697

Locations

periplasmic spaceGO:0042597

Candidate periplasmic substrate-binding protein adjacent to betC; direct ligand binding and coupling to BetE are untested.

Part: qualified BetT cargo-scope candidate (optional)
Ruegeria BetT cargo-scope candidateTransport Stepruegeria_bett_candidate_context

A choline-depletion phenotype and a partial COS-growth phenotype identify a pathway candidate. Co-transcription with betA leaves insertion polarity unresolved; neither choline nor COS cargo is established for this protein.

Annotons

BetT transport candidate
ruegeria_bett_candidate
Participant: Family: Ruegeria BetT-type membrane transport proteins with verified locus identity
Family:
Ruegeria BetT-type membrane transport proteins with verified locus identity The frozen target record has no PANTHER/InterPro assignment. Its eggNOG COG1292 classification and the paper's BCCT-type assignment support transporter-family plausibility, while substrate specificity remains unresolved. No PANTHER identifier is invented from the BetT name.
Representative Members: SPO1087 (RUEPO)UniProtKB:Q5LUG7

Function

transmembrane transporter activity Proposed activity class from the BCCT/COG1292 family assignment and multipass membrane architecture. This free-text candidate descriptor does not assert a GO molecular function, transported cargo or coupling mechanism, and does not satisfy the required COS import step.

Optional candidate implicated by an insertion/depletion phenotype. The co-transcribed betA oxidation step is a possible downstream confound. No choline- or COS-import molecular function is asserted for this locus.

PMID:26058574
Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade.
The native DSS-3 betC mutant supports COS utilization through SPO1083; the BetT COS-growth phenotype is partial and does not identify a directly measured COS uptake reaction.
Growth of the ΔbetT::Gm mutant on COS (μ = 0.027 ± 0.001 h−1) was also affected
PMID:40801533
Novel regulatory mechanism of choline-O-sulfate and choline catabolism by two BetIs in Alphaproteobacteria.
This later regulatory study labels BetT as a choline/COS transporter in a proposed diagram. Neither cargo assignment is established by the diagram; the earlier insertion/depletion phenotype remains confounded by the co-transcribed betA oxidation step.
BetT, choline and choline-O-sulfate transporter