TreSB (PP_4059) is a large bifunctional carbohydrate enzyme with an N-terminal GH13 TreS domain and a C-terminal maltokinase domain. It interconverts maltose and alpha,alpha-trehalose (EC 5.4.99.16) and separately phosphorylates maltose with ATP to produce alpha-maltose 1-phosphate (EC 2.7.1.175), the donor used by adjacent GlgE.
Definition: Catalysis of the reaction D-maltose + ATP = alpha-maltose 1-phosphate + ADP + H(+).
Justification: TreSB has an explicitly assigned EC 2.7.1.175/RHEA:31915 maltokinase reaction and a TreS-maltokinase C-terminal domain, but the local GO ontology has no substrate-specific molecular-function term for this activity.
Parent term: carbohydrate kinase activity
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: TreSB is catalytic, but this root term hides both specific reactions. Reason: GO:0047471 captures the TreS reaction and a separate kinase annotation is needed for maltose phosphorylation, so the root catalytic term should not be propagated as an independent function. Supporting Evidence: file:PSEPK/treSB/treSB-uniprot.txt EC=2.7.1.175 file:PSEPK/treSB/treSB-uniprot.txt EC=5.4.99.16 |
| GO:0005975 carbohydrate metabolic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: Both TreSB reactions directly interconvert carbohydrate metabolites. Reason: The annotation is correct but too broad to describe TreSB's role. It is marked as over-annotated without assigning the protein every downstream reaction in trehalose or alpha-glucan metabolism. Supporting Evidence: file:PSEPK/treSB/treSB-uniprot.txt Reaction=D-maltose = alpha,alpha-trehalose |
| GO:0047471 maltose alpha-D-glucosyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: The TreS domain interconverts D-maltose and alpha,alpha-trehalose. Reason: The record assigns EC 5.4.99.16/RHEA:15145, a TreS-specific N-terminal domain, and PTHR10357:SF219 named maltose alpha-D-glucosyltransferase. This supports one half of the bifunctional protein but not its separate maltokinase reaction. Supporting Evidence: file:PSEPK/treSB/treSB-uniprot.txt Reaction=D-maltose = alpha,alpha-trehalose file:PSEPK/treSB/treSB-uniprot.txt DR InterPro; IPR012810; TreS/a-amylase_N. |
| GO:0019200 carbohydrate kinase activity | IC file:PSEPK/treSB/treSB-uniprot.txt | NEW | Summary: The C-terminal maltokinase domain phosphorylates D-maltose with ATP to produce alpha-maltose 1-phosphate. Reason: UniProt assigns EC 2.7.1.175/RHEA:31915 and a TreS-maltokinase C-terminal domain, but the seeded GOA lacks the kinase half of this bifunctional protein. GO lacks a substrate-specific maltokinase term, and GO:0019200 is the most specific available parent for phosphorylation of a carbohydrate substrate. Supporting Evidence: file:PSEPK/treSB/treSB-uniprot.txt Reaction=D-maltose + ATP = alpha-maltose 1-phosphate + ADP + H(+) file:PSEPK/treSB/treSB-uniprot.txt DR InterPro; IPR012811; TreS_maltokin_C_dom. |
| GO:0030979 alpha-glucan biosynthetic process | IC file:PSEPK/treSB/treSB-uniprot.txt | NEW | Summary: The fused maltokinase activity supplies alpha-maltose 1-phosphate directly to the adjacent GlgE polymer-extension reaction. Reason: The Mak half of TreSB produces the dedicated donor consumed by GlgE, supporting direct participation of the fused protein in alpha-glucan biosynthesis without assigning the reversible TreS reaction alone to that process. The evidence is indirect and of two kinds: the C-terminal region of Q88FN0 is classified as a TreS-fused maltokinase domain (InterPro IPR012811, NCBIfam TIGR02457), and the TreS-Pep2(maltokinase)-GlgE-GlgB route to alpha-glucan, with maltose 1-phosphate as the GlgE donor, was established experimentally in Mycobacterium tuberculosis (PMID:20305657), not in P. putida. The ARBA-only UniProt reaction line and the neighbouring glgE record are not cited. Supporting Evidence: file:PSEPK/treSB/treSB-uniprot.txt InterPro; IPR012811; TreS_maltokin_C_dom. file:PSEPK/treSB/treSB-uniprot.txt NCBIfam; TIGR02457; TreS_Cterm; 1. PMID:20305657 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. |
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