Pathway · 4 proteins
Folding and stabilization
Chaperone systems address non-native protein conformations.
How it works
- DnaJ/DnaK, GroEL/GroES and Hsp33-family HslO represent different ways of limiting harmful protein aggregation or assisting recovery of non-native proteins.
- DnaK-associated and GroEL-associated cycles can use ATP-dependent changes in client binding. Hsp33-family stabilization represents a different stress-responsive mechanism rather than another GroEL subunit.
- Stabilization can preserve a client for subsequent folding or removal, but recovery is not guaranteed. The triggering conditions, handoff partners and clients of each VF5 annotation require separate evidence.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| 33 kDa chaperonin | — | — | — | 325 | Step named |
| Co-chaperonin GroES | — | — | — | 122 | Step named |
| Chaperonin GroEL | 5.6.1.7 | ATP + H2O + an unfolded polypeptide = ADP + phosphate + a folded polypeptide. | — | 545 | Step named |
| Chaperone protein DnaK | — | — | — | 632 | Step named |
Origins
Could the first proteins fold correctly without help?
How it was discovered
- 1972Christian Anfinsen receives the Nobel Prize for showing that a protein chain can fold into its working shape on its own under defined laboratory conditions.Solomon, Berg & Martin, Biology, PDF p. 99
Anfinsen's work supports the view that the amino-acid sequence determines a protein's shape.
Folding on its own works under defined laboratory conditions; inside a crowded cell many proteins need chaperones to fold or to stay folded. That holds even more at the temperatures where Aquifex lives. Four proteins in this pathway provide that help.
A sequence that folds into a working shape is itself the information that has to be explained.
From the books: Solomon, Berg & Martin, Biology, PDF p. 99.
The wider question for this part of the cell: origins for building proteins and folding them.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: Ribosomal subunits · Translation interface · RNA maturation · Translation cycle · Protein translocation · Protein turnover · Recycling and rescue · Early folding support · Protein targeting · Ribosome · Protein export · Not yet placed in a pathway