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Peptide-binding specificity of the molecular chaperone BiP
G C Flynn1, J Pohl, M T Flocco
1Program in Cellular Biochemistry and Biophysics, Rockefeller Research Laboratory, Sloan-Kettering Institute, New York, New York 10021.
Nature
|October 24, 1991
Summary
Heat-shock proteins (hsp70s) act as molecular chaperones by recognizing unfolded proteins. Their peptide-binding site specifically selects aliphatic residues, mimicking a folded protein environment.
Area of Science:
- Protein folding and molecular chaperones
- Biochemistry and molecular biology
Background:
- Heat-shock proteins (hsp70s) are essential molecular chaperones.
- Hsp70s differentiate between folded and unfolded proteins.
- This discrimination relies on the amino-acid specificity of their peptide-binding site.
Purpose of the Study:
- To investigate the specificity of the hsp70 peptide-binding site.
- To understand how hsp70s recognize unfolded proteins.
Main Methods:
- Utilized a set of peptides with random sequences but defined lengths.
- Analyzed the binding preferences of the hsp70 peptide-binding site.
Main Results:
- The peptide-binding site exhibits specificity for aliphatic amino acid residues.
- These residues are accommodated in an energetically favorable state, similar to the interior of a folded protein.
Conclusions:
- Hsp70s recognize unfolded proteins through specific interactions with aliphatic residues.
- The binding site's environment is key to its chaperone function.