Novel Insights into the Human Hsc70 Structure by Cross-Linking Mass Spectrometry and Molecular Modeling
Aleksandr Melikov1, Vsevolod Viliuga2,3,4, Daniel Kavan1
1Institute of Microbiology, the Czech Academy of Sciences , Prague14220, Czech Republic.
Journal of Proteome Research
|August 7, 2026
Summary
Heat shock cognate protein 70 (Hsc70) forms dimers with distinct structures in ATP and ADP states. Cochaperone DnaJB1 influences this equilibrium, impacting Hsc70 function and protein folding.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Heat shock cognate protein 70 (Hsc70) is a crucial molecular chaperone.
- Hsp70 family proteins are ATP-dependent machines involved in protein folding and stress response.
- The oligomeric states and structural dynamics of Hsc70 dimers are not well understood.
Purpose of the Study:
- To investigate the structural organization of Hsc70 dimers.
- To understand the influence of nucleotide state and cochaperones on Hsc70 dimer formation.
Main Methods:
- Chemical cross-linking
- High-resolution Fourier transform mass spectrometry (FTMS)
- 15N isotopic labeling
- AlphaLink2 for structural modeling
Main Results:
- Identified distinct ATP- and ADP-state dimer conformations of Hsc70.
- Observed a shift in dimer-monomer equilibrium upon addition of cochaperone DnaJB1.
- Demonstrated enhanced ATP hydrolysis and formation of intermediate species in the presence of DnaJB1.
Conclusions:
- Hsc70 dimer population is structurally heterogeneous.
- Nucleotide state and cochaperone interactions critically regulate Hsc70 dimer structure and function.
