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Updated: Jan 13, 2026
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Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo
Published on: October 23, 2016
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Chaperone dependency during biogenesis does not correlate with chaperone dependency during refolding.
Divya Yadav1, İdil I Demiralp1,2, Mark Fakler1
1Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA.
Molecular Systems Biology
|October 29, 2025
Summary
Molecular chaperones aid protein folding, but their in vivo roles differ from in vitro refolding. Deleting E. coli chaperones DnaKJ and trigger factor revealed that co-translational folding is crucial for some proteins, not just chaperone assistance.
Area of Science:
- Molecular biology
- Protein folding
- Biochemistry
Background:
- Proteins require molecular chaperones for proper folding into functional structures.
- In vivo protein biogenesis roles of chaperones may differ from in vitro refolding functions.
Purpose of the Study:
- To investigate the in vivo structural impact of deleting key E. coli chaperones, trigger factor and DnaKJ.
- To determine if proteins unable to refold in vitro rely more on chaperones for in vivo folding.
Main Methods:
- Limited proteolysis mass spectrometry (LiP-MS) was employed to analyze structural changes in the E. coli proteome.
- Comparative analysis of protein structures upon deletion of trigger factor and DnaKJ chaperones.
Main Results:
- DnaKJ deletion caused widespread structural changes in soluble E. coli proteins.
- Trigger factor deletion affected the structures of only a limited number of proteins.
- Proteins that cannot refold spontaneously or with in vitro chaperone assistance are not necessarily chaperone-dependent in vivo.
Conclusions:
- Chaperone-nonrefolding proteins are likely obligate co-translational folders.
- The vectorial process of co-translational folding acts as a primary "chaperone" for certain E. coli proteins.
- In vivo protein folding mechanisms are complex and context-dependent.
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