GroES (Cpn10/Hsp10, ~10 kDa) is the bacterial co-chaperonin partner of the GroEL chaperonin. It assembles as a heptameric, dome-shaped ring that binds in an ATP-dependent manner to the apical surface of a GroEL ring, capping the central cavity to form an enclosed nano-cage. Encapsulation of non-native substrate proteins in this chamber provides a folding-permissive environment that promotes productive folding and prevents aggregation, with cyclic GroES binding and release driven by the GroEL ATPase. GroES acts in the cytoplasm and is a constitutive component of the cellular proteostasis machinery; in Pseudomonas putida the groES-groEL operon is part of the sigma-32 (RpoH)-controlled heat-shock regulon and is induced under thermal, solvent, pressure and other proteotoxic stresses. The GroEL/GroES system is essential for viability in most bacteria.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005524 ATP binding | IEA GO_REF:0000002 | REMOVE | Summary: ATP binding within the GroEL/GroES chaperonin system is a property of GroEL, not of the GroES co-chaperonin. GroES itself has no nucleotide-binding site; its binding to GroEL is triggered by ATP binding to GroEL. Reason: This InterPro-based IEA annotation conflates the ATP-dependent GroEL/GroES cycle with intrinsic ATP binding by GroES. GroES does not bind ATP; ATP binding is performed by the GroEL subunit. The annotation is an over-propagation from a family-level signature and is not appropriate for the co-chaperonin. |
| GO:0005737 cytoplasm | IEA GO_REF:0000120 | ACCEPT | Summary: GroES is a soluble cytoplasmic protein that binds cytoplasmic GroEL to form folding chambers. UniProt subcellular location and the conserved biology of the GroEL/GroES system support cytoplasmic localization. |
| GO:0006457 protein folding | IEA GO_REF:0000120 | ACCEPT | Summary: Assisting protein folding is the central biological role of GroES, which together with GroEL encapsulates non-native substrates in a folding chamber. This is the core process annotation for the gene. In P. putida KT2440 the groES (PP_1360)-groEL (PP_1361) operon is induced under heat, pressure and aromatic-solvent stress as part of the sigma-32/RpoH proteostasis regulon (see deep research). Supporting Evidence: file:PSEPK/groES/groES-deep-research-falcon.md GroES participates in bacterial proteostasis and the heat-shock/stress response by assisting GroEL-mediated folding; in KT2440 groES/PP_1360 is induced together with groEL and rpoH under pressure and aromatic-solvent stress. |
| GO:0044183 protein folding chaperone | IEA GO_REF:0000002 | ACCEPT | Summary: GroES acts as a co-chaperonin that, in cooperation with GroEL, mediates protein folding. This molecular-function term captures the chaperone activity and is a core function annotation. |
| GO:0046872 metal ion binding | IEA GO_REF:0000118 | REMOVE | Summary: GroES has no established metal-ion-binding function. The co-chaperonin is a small beta-barrel protein whose function is to cap GroEL; metal binding is not part of its mechanism and is not described in UniProt or the structural literature for GroES. Reason: This is a TreeGrafter/PANTHER tree-based over-annotation without support in the experimental or structural literature for GroES family proteins. Metal ion binding is not a known molecular function of the co-chaperonin. |
| GO:0051087 protein-folding chaperone binding | IEA GO_REF:0000118 | ACCEPT | Summary: GroES binds directly to the GroEL chaperonin, its obligate functional partner, capping the GroEL ring to form the folding chamber. Binding to the GroEL chaperonin is well supported and central to GroES function. |
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