TreS-Mak-GlgE branched alpha-glucan biosynthesis

A reusable bacterial pathway that channels trehalose into branched alpha-glucan. Trehalose synthase operating in the catabolic direction forms maltose, maltokinase converts maltose to alpha-maltose 1-phosphate, GlgE uses that activated donor to extend alpha-1,4-glucan chains by maltosyl units, and GlgB introduces alpha-1,6 branches. TreS and Mak may be separate proteins or domains of one fusion protein; that architectural variation does not change the four reaction roles.

MODULE:tres_mak_glge_branched_alpha_glucan_biosynthesisDRAFTCONCRETEMetabolic Pathwaymodules/tres_mak_glge_branched_alpha_glucan_biosynthesis.yaml
alpha-glucan biosynthetic processGO:0030979
PMID:20305657
Self-poisoning of Mycobacterium tuberculosis by targeting GlgE in an alpha-glucan pathway.
Biochemical genetics established a four-reaction route from trehalose to alpha-glucan mediated by TreS, Pep2/Mak, GlgE, and GlgB.
We describe a new pathway from trehalose to alpha-glucan in Mycobacterium tuberculosis comprising four enzymatic steps mediated by TreS, Pep2, GlgE (which has been identified as a maltosyltransferase that uses maltose 1-phosphate) and GlgB.
PMID:24689960
Structural insight into how Streptomyces coelicolor maltosyl transferase GlgE binds α-maltose 1-phosphate and forms a maltosyl-enzyme intermediate.
Structural and biochemical work defines GlgE as the maltose 1-phosphate-dependent maltosyltransferase of a bacterial alpha-glucan pathway.
GlgE (EC 2.4.99.16) is an α-maltose 1-phosphate:(1→4)-α-d-glucan 4-α-d-maltosyltransferase of the CAZy glycoside hydrolase 13_3 family.
PMID:32267616
Pseudomonas putida KT2440 is naturally endowed to withstand industrial-scale stress conditions.
KT2440 transcriptional profiling under glucose starvation directly links glgB expression to glycogen biosynthesis and shows that the organism mobilizes glycogen during rapid carbon limitation.
In addition, upregulation was found for genes belonging to glycogen biosynthesis (glgA, glgB) and its degradation (glgX, glgP, malQ).
file:projects/P_PUTIDA/deep-research/PSEPK__tres_mak_glge_branched_alpha_glucan_biosynthesis__ppu00500-deep-research-openscientist.md
OpenScientist PSEPK ppu00500 TreS-Mak-GlgE pathway report
Taxon-specific retrieval independently found all four reaction roles in KT2440 and narrowed them to treSB, glgE, and glgB. Its stronger claims about pathway primacy, operon structure, and GlgC absence remain hypotheses rather than module-defining evidence.
GO:0030979
alpha-glucan biosynthetic process
GO:0030979 captures formation of alpha-glucan represented by the GlgE-dependent extension and GlgB-dependent branching reactions.
file:PSEPK/treSB/treSB-uniprot.txt
UniProtKB entry for PSEPK TreSB
Q88FN0 carries both trehalose synthase EC 5.4.99.16 and maltokinase EC 2.7.1.175 reactions.
file:PSEPK/glgE/glgE-uniprot.txt
UniProtKB entry for PSEPK GlgE
Q88FM9 is assigned the maltose-1-phosphate-dependent alpha-glucan extension reaction Rhea 42692.
file:PSEPK/glgB/glgB-uniprot.txt
UniProtKB entry for PSEPK GlgB
Q88FN1 is a reviewed 1,4-alpha-glucan branching enzyme.

TreS and Mak occur as separate proteins in some bacteria and as a bifunctional fusion in others. The Pseudomonas putida KT2440 fusion TreSB is therefore represented as the same exemplar in two reaction leaves without collapsing their distinct activities. The module starts with trehalose and ends with branched alpha-glucan; trehalose biosynthesis, glucan priming, degradation, and downstream storage or envelope roles are outside its boundary. Exact EC and Rhea reactions preserve the substrate specificity that the available broad GO terms for Mak and GlgE do not capture. The KT2440 glucose-starvation transcriptome co-upregulates glgA and glgB, which is contextual evidence that GlgB can be shared with the classical GlgA-dependent glycogen route rather than being dedicated to this module.

5Nodes
4Parts
0Variant Sets
0Variants
4Annotons
3Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:tres_mak_glge_branched_alpha_glucan_biosynthesis deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

4 gene-function check(s) reflected in core functions · 0 conflict(s) · 7 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
tres_activity TreS-Mak fusion (Pseudomonas putida KT2440)
UniProtKB:Q88FN0
Family Representative 		maltose alpha-D-glucosyltransferase activity
GO:0047471 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
tres_activity TreS (Mycobacterium tuberculosis H37Rv)
UniProtKB:P9WQ19
Family Representative 		maltose alpha-D-glucosyltransferase activity
GO:0047471 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
mak_activity TreS-Mak fusion (Pseudomonas putida KT2440)
UniProtKB:Q88FN0
Family Representative 		carbohydrate kinase activity
GO:0019200 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
mak_activity Mak (Mycobacterium tuberculosis H37Rv)
UniProtKB:O07177
Family Representative 		carbohydrate kinase activity
GO:0019200 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
glge_activity GlgE (Pseudomonas putida KT2440)
UniProtKB:Q88FM9
Family Representative 		hexosyltransferase activity
GO:0016758 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
glge_activity GlgE (Mycobacterium tuberculosis H37Rv)
UniProtKB:P9WQ17
Family Representative 		hexosyltransferase activity
GO:0016758 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
glgb_activity GlgB (Pseudomonas putida KT2440)
UniProtKB:Q88FN1
Family Representative 		1,4-alpha-glucan branching enzyme activity
GO:0003844 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
glgb_activity GlgB (Mycobacterium tuberculosis H37Rv)
UniProtKB:P9WN45
Family Representative 		1,4-alpha-glucan branching enzyme activity
GO:0003844 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
tres_activity TreS trehalose synthase family
PANTHER:PTHR10357:SF219
Family 		maltose alpha-D-glucosyltransferase activity
GO:0047471 		Family Supported
Family review supports GO:0047471 for PANTHER:PTHR10357:SF219. Trehalose synthase activity is safe for the SF219 TreS clade rooted at PTN000039847 (M. tuberculosis Rv0126, Pimelobacter sp. R48 TreS). It must not descend from the family root. A second, Pseudomonas-type TreS group defined by NCBIfam TIGR02455 and InterPro IPR012665 (P. stutzeri CJ38 TreS Q9LAS5, P. putida KT2440 TreSA Q88IT1) also carries the activity, shown for the CJ38 enzyme, but its members are placed in PTHR10357 only at family level with no subfamily, so neither SF219 nor the PAINT node reaches them; for that group the activity has to be assigned from the TIGR02455/IPR012665 signature rather than from PANTHER.
mak_activity maltokinase family
Family 		carbohydrate kinase activity
GO:0019200 		Family Id Missing
The family has no identifier linking it to a curated family review.
glge_activity GlgE maltosyltransferase family
PANTHER:PTHR47786
Family 		hexosyltransferase activity
GO:0016758 		Family Review Missing
No supported structured family review is available for PANTHER:PTHR47786.
glgb_activity GlgB alpha-glucan branching-enzyme family
PANTHER:PTHR43651
Family 		1,4-alpha-glucan branching enzyme activity
GO:0003844 		Family Scope Restricted
GO:0003844 is SUBFAMILY_ONLY; this family grounding does not establish the allowed subfamily scope. Asserted by glycogen_metabolism_fungal, glycogen_biosynthesis, tres_mak_glge_branched_alpha_glucan_biosynthesis and glycogen_synthesis_and_mobilization; accepted by GLC3. Restricted to the branching-enzyme clade PTN000040010; TreZ (SF11) lacks it.

Gene-review completeness (3/7 grounded genes reviewed)

3 complete review(s) · 3 with deep research · 4 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
glgB Q88FN1 ✓ ✓ ✓
glgE Q88FM9 ✓ ✓ ✓
Mak (Mycobacterium tuberculosis H37Rv) O07177 ✗ — —
GlgB (Mycobacterium tuberculosis H37Rv) P9WN45 ✗ — —
GlgE (Mycobacterium tuberculosis H37Rv) P9WQ17 ✗ — —
TreS (Mycobacterium tuberculosis H37Rv) P9WQ19 ✗ — —
treSB Q88FN0 ✓ ✓ ✓

Details

Context
bacteriaNCBITaxon:2
TreS-Mak-GlgE branched alpha-glucan biosynthesisMetabolic Pathwaytres_mak_glge_branched_alpha_glucan_biosynthesis
alpha-glucan biosynthetic processGO:0030979
Context
bacteriaNCBITaxon:2

Connections

TreS supplies D-maltose to Mak.
Mak supplies alpha-maltose 1-phosphate to GlgE.
GlgB branches the alpha-1,4-glucan chains extended by GlgE.
Part 1: trehalose isomerization to maltose
TreS-dependent maltose formationReactiontres_maltose_formation

Annotons

TreS trehalose synthase activity in the maltose-forming direction
tres_activity
Participant: Family: TreS trehalose synthase family
Family:
TreS trehalose synthase familyPANTHER:PTHR10357:SF219
Representative Members: TreS-Mak fusion (Pseudomonas putida KT2440)UniProtKB:Q88FN0 TreS (Mycobacterium tuberculosis H37Rv)UniProtKB:P9WQ19

Function

maltose alpha-D-glucosyltransferase activityGO:0047471
Substrates: alpha,alpha-trehalose
Products: D-maltose

Converts trehalose to the maltokinase substrate.

Part 2: maltose 1-phosphate formation
Mak-dependent alpha-maltose 1-phosphate formationReactionmak_maltose_1_phosphate_formation

Annotons

Mak maltokinase activity
mak_activity
Participant: Family: maltokinase family
Family:
maltokinase family
Representative Members: TreS-Mak fusion (Pseudomonas putida KT2440)UniProtKB:Q88FN0 Mak (Mycobacterium tuberculosis H37Rv)UniProtKB:O07177

Function

carbohydrate kinase activityGO:0019200
Substrates: D-maltose ATP
Products: alpha-maltose 1-phosphate ADP

Processes

alpha-glucan biosynthetic processGO:0030979

Produces the activated maltosyl donor used by GlgE.

Part 3: alpha-1,4-glucan chain extension
GlgE-dependent alpha-glucan extensionReactionglge_alpha_glucan_extension

Annotons

GlgE maltose-1-phosphate maltosyltransferase activity
glge_activity
Participant: Family: GlgE maltosyltransferase family
Family:
GlgE maltosyltransferase familyPANTHER:PTHR47786
Representative Members: GlgE (Pseudomonas putida KT2440)UniProtKB:Q88FM9 GlgE (Mycobacterium tuberculosis H37Rv)UniProtKB:P9WQ17

Function

hexosyltransferase activityGO:0016758
Substrates: alpha-maltose 1-phosphate alpha-1,4-glucan acceptor
Products: alpha-1,4-glucan extended by two glucose residues phosphate

Processes

alpha-glucan biosynthetic processGO:0030979

Builds the linear alpha-1,4-glucan backbone.

Part 4: alpha-glucan branching
GlgB-dependent alpha-1,6 branchingReactionglgb_alpha_glucan_branching

Annotons

GlgB 1,4-alpha-glucan branching activity
glgb_activity
Participant: Family: GlgB alpha-glucan branching-enzyme family
Family:
GlgB alpha-glucan branching-enzyme familyPANTHER:PTHR43651
Representative Members: GlgB (Pseudomonas putida KT2440)UniProtKB:Q88FN1 GlgB (Mycobacterium tuberculosis H37Rv)UniProtKB:P9WN45

Function

1,4-alpha-glucan branching enzyme activityGO:0003844
Substrates: alpha-1,4-glucan chain
Products: alpha-1,4-glucan containing alpha-1,6 branches

Processes

alpha-glucan biosynthetic processGO:0030979

Converts extended linear chains into branched alpha-glucan.