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Updated: Mar 29, 2026

Detection of the pH-dependent Activity of Escherichia coli Chaperone HdeB In Vitro and In Vivo
Published on: October 23, 2016
HdeB chaperone activity is coupled to its intrinsic dynamic properties
Jienv Ding1,2, Chengfeng Yang3,2, Xiaogang Niu3,2
1College of Life Sciences, Peking University, Beijing 100871, China.
Bacterial acid resistance relies on chaperones like HdeB. Unlike HdeA, HdeB uses internal protein dynamics, not structural changes, for acid protection at pH 4-5, maintaining its dimer form.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Enteric bacteria face extreme stomach acidity, requiring robust acid resistance mechanisms.
- Periplasmic chaperones, such as HdeA and HdeB, are crucial for preventing protein denaturation and maintaining bacterial viability.
- HdeA functions via acid-induced unfolding, but HdeB's mechanism at its optimal pH (4-5) remains unclear.
Purpose of the Study:
- To investigate the dynamic properties of HdeB using Nuclear Magnetic Resonance (NMR) spectroscopy.
- To elucidate the mechanism of HdeB's chaperone activity at its optimal activation pH.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy was employed to study HdeB.
- Analysis focused on micro- to milli-second timescale conformational dynamics.
Main Results:
- HdeB exhibits significant conformational exchanges in the micro- to milli-second timescale at neutral and near-neutral pH.
- Optimal HdeB activity occurs under conditions where these dynamics are prevalent.
- HdeB maintains a well-folded dimer structure at its optimal activation pH (4-5).
Conclusions:
- HdeB's acid resistance mechanism is intrinsically linked to its dynamic properties, not major structural transitions.
- HdeB's functional mechanism differs significantly from that of its homolog, HdeA.
- Understanding HdeB dynamics provides insights into bacterial acid tolerance strategies.
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