The 70 kDa heat shock proteins (Hsp70) are a family of molecular chaperones involved in protein folding, aggregate prevention, and protein disaggregation. They consist of the substrate‐binding domain (SBD) that binds client substrates, and the nucleotide‐binding domain (NBD), whose cycles of nucleotide hydrolysis and exchange underpin the activity of the chaperone. To characterize the structure–function relationships that link the binding state of the NBD to its conformational behavior, we analyzed the dynamics of the NBD of the Hsp70 chaperone from
Immunoglobulin Binding Protein (BiP) is a chaperone and molecular motor belonging to the Hsp70 family, involved in the regulation of important biological processes such as synthesis, folding and translocation of proteins in the Endoplasmic Reticulum. BiP has two highly conserved domains: the N‐terminal Nucleotide‐Binding Domain (NBD), and the C‐terminal Substrate‐Binding Domain (SBD), connected by a hydrophobic linker. ATP binds and it is hydrolyzed to ADP in the NBD, and BiP's extended polypeptide substrates bind in the SBD. Like many molecular motors, BiP function depends on both structural and catalytic properties that may contribute to its performance. One novel approach to study the mechanical properties of BiP considers exploring the changes in the viscoelastic behavior upon ligand binding, using a technique called nano‐rheology. This technique is essentially a traditional rheology experiment, in which an oscillatory force is directly applied to the protein under study, and the resulting average deformation is measured. Our results show that the folded state of the protein behaves like a viscoelastic material, getting softer when it binds nucleotides‐ ATP, ADP, and AMP‐PNP‐, but stiffer when binding HTFPAVL peptide substrate. Also, we observed that peptide binding dramatically increases the affinity for ADP, decreasing it dissociation constant (
- NSF-PAR ID:
- 10075959
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Protein Science
- Volume:
- 27
- Issue:
- 8
- ISSN:
- 0961-8368
- Page Range / eLocation ID:
- p. 1418-1426
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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