Subsystem: Threonine anaerobic catabolism gene cluster

This subsystem's description is:

This small Subsystem describes an extended tdcABCDEFG operon (gene cluster), which encodes components of an anaerobically inducible, catabolite-repressible pathway, generating one molecule of ATP from the degradation of L-threonine to propionate via 2-ketobutyrate as an intermediate [1].

This gene cluster apparently also plays a role in anaerobic degradation of serine: (i) TdcE (e.g. fig|83333.1.peg.3060) has both pyruvate formate-lyase and 2-ketobutyrate formate-lyase activity; (ii) the TdcD protein is a propionate/acetate kinase [1]; (iii) L-threonine transporter, anaerobically inducible (TdcC, e.g. fig|83333.1.peg.3062) is also active with L-serine [2]; (iv) furthermore, a predicted L-serine dehydratase (EC 4.3.1.17) TdcG is a part of this operon and a putative L-serine transporter is located immediately downstream of it.

Other functional roles involved in this catabolic pathway, but encoded outside of the tdc operon have been included here as well:
- Pyruvate formate-lyase activating enzyme, which is also an essential activator of Threonine dehydratase, catabolic (EC 4.3.1.19), a glycyl radical enzyme [1];
- Phosphate acetyltransferase (PAT) - a necessary component of the proposed L-threonine to propionate pathway (see diagram)
- Acetate kinase (ACK), because it appears to contribute significantly to propionate production [1]

This operon is present in many (but not all) Enterobacteriales


Variant codes:

1 = a complete tdcABCDEFG operon, as in E. coli K12
2 = a shorter variant of the operon with one or more genes missing (sequencing mistakes and uncalled ORFs excluding)
-1 = Tdc operon in not detectable in a genome

For more information, please check out the description and the additional notes tabs, below

DiagramFunctional RolesSubsystem SpreadsheetDescriptionAdditional NotesScenarios 

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Group Alias
Abbrev.Functional RoleReactionsScenario ReactionsGOLiterature
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Taxonomy Pattern 
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active
TdcRTdcAThrDHTTPKKBFLTdcFTdcGSTPATACKPFLaPFL
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This small Subsystem describes an extended tdcABCDEFG operon (gene cluster), which encodes components of an anaerobically inducible, catabolite-repressible pathway, generating one molecule of ATP from the degradation of L-threonine to propionate via 2-ketobutyrate as an intermediate [1].

This gene cluster apparently also plays a role in anaerobic degradation of serine: (i) TdcE (e.g. fig|83333.1.peg.3060) has both pyruvate formate-lyase and 2-ketobutyrate formate-lyase activity; (ii) the TdcD protein is a propionate/acetate kinase [1]; (iii) L-threonine transporter, anaerobically inducible (TdcC, e.g. fig|83333.1.peg.3062) is also active with L-serine [2]; (iv) furthermore, a predicted L-serine dehydratase (EC 4.3.1.17) TdcG is a part of this operon and a putative L-serine transporter is located immediately downstream of it.

Other functional roles involved in this catabolic pathway, but encoded outside of the tdc operon have been included here as well:
- Pyruvate formate-lyase activating enzyme, which is also an essential activator of Threonine dehydratase, catabolic (EC 4.3.1.19), a glycyl radical enzyme [1];
- Phosphate acetyltransferase (PAT) - a necessary component of the proposed L-threonine to propionate pathway (see diagram)
- Acetate kinase (ACK), because it appears to contribute significantly to propionate production [1]

This operon is present in many (but not all) Enterobacteriales


Variant codes:

1 = a complete tdcABCDEFG operon, as in E. coli K12
2 = a shorter variant of the operon with one or more genes missing (sequencing mistakes and uncalled ORFs excluding)
-1 = Tdc operon in not detectable in a genome
References:

1. Heßlinger C., S.A. Fairhurst & G. Sawers. 1998. Novel keto acid formate-lyase and propionate kinase enzymes are components of an anaerobic pathway in Escherichia coli that degrades L-threonine to propionate. Mol.Microbiol.,27(2), p.477

2. Sumantran, V.N., Schweizer, H.P., Datta, P. (1990) A novel membrane-associated threonine permease encoded by the tdcC gene of Escherichia coli. J Bacteriol 27: 4288–4294

3. Goss TJ, Schweizer HP, Datta P (1988). "Molecular characterization of the tdc operon of Escherichia coli K-12." J Bacteriol 1988;170(11);5352-9. PMID: 3053659

4. Hagewood BT, Ganduri YL, Datta P. Functional analysis of the tdcABC promoter of Escherichia coli: roles of TdcA and TdcR. J Bacteriol. 1994 Oct;176(20):6214-20.

5. Goss TJ, Datta P. Molecular cloning and expression of the biodegradative threonine dehydratase gene (tdc) of Escherichia coli K12. Mol Gen Genet. 1985;201(2):308-14.

6. Ganduri YL, Sadda SR, Datta MW, Jambukeswaran RK, Datta P. TdcA, a transcriptional activator of the tdcABC operon of Escherichia coli, is a member of the LysR family of proteins. Mol Gen Genet. 1993 Sep;240(3):395-402.

7. Schweizer HP, Datta P. Genetic analysis of the tdcABC operon of Escherichia coli K-12. J Bacteriol. 1988 Nov;170(11):5360-3.

Currently selected organism: Escherichia coli 2731150 (open scenarios overview page for organism)