Interaction of Hsp70 chaperones with substrates
S Rüdiger1, A Buchberger, B Bukau
1Zentrum für Molekulare Biologie, Universität Heidelberg, Germany.
Nature Structural Biology
|May 1, 1997
Summary
The structure of E. coli DnaK
Area of Science:
- Molecular Biology
- Biochemistry
Background:
- Heat shock proteins (Hsp70) are crucial molecular chaperones involved in protein folding and homeostasis.
- Understanding Hsp70 substrate recognition is key to deciphering their cellular functions.
Purpose of the Study:
- To determine the structure of the substrate binding domain of Escherichia coli Hsp70 chaperone, DnaK.
- To biochemically characterize the recognition motif within substrates bound by DnaK.
Main Methods:
- X-ray crystallography to determine the 3D structure of the DnaK substrate binding domain.
- Biochemical assays to analyze the interaction between DnaK and various peptide substrates.
Main Results:
- The precise structure of the DnaK substrate binding domain was elucidated.
- DnaK recognizes extended peptide strands with up to five consecutive hydrophobic residues.
- Positively charged residues outside the binding cavity contribute to substrate recognition.
Conclusions:
- Structural and biochemical data provide insights into Hsp70-polypeptide interactions.
- The identified motif highlights the specificity of DnaK substrate binding.
Related Concept Videos
03:00Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
01:37Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
01:27Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
01:32Export of Misfolded Proteins out of the ER
After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
03:00Molecular Chaperones and Protein Folding
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
01:26Bacterial Protein Maturation
Bacterial protein maturation is a tightly regulated process that ensures newly synthesized polypeptides achieve correct functional conformations. This maturation involves a series of modifications, folding events, and quality control steps, often assisted by specialized chaperone proteins.N-Terminal ModificationsThe maturation of bacterial polypeptides begins cotranslationally as the polypeptide exits the ribosome. The first amino acid, N-formylmethionine (fMet), is typically modified at the...