What do Hsp70 and Hsp60 primarily interact with in misfolded proteins?

Hsp70 and Hsp60 are types of heat shock proteins that play critical roles in protein folding and the protection of cells under stress conditions. Their primary interaction with misfolded proteins involves exposed hydrophobic residues.

When proteins misfold, their hydrophobic amino acids, which are normally buried within the protein structure, become exposed to the aqueous environment. These exposed hydrophobic regions can lead to aggregation or further misfolding if not properly managed. Hsp70 and Hsp60 recognize these exposed hydrophobic residues, binding to them to stabilize the misfolded protein and facilitate its correct refolding or degradation.

This ability to target hydrophobic surfaces is central to the function of these chaperones, as it prevents further interactions that could lead to aggregation and misfolding, allowing the cell to maintain protein homeostasis. Thus, the interaction with exposed hydrophobic residues is crucial for their role in managing protein folding under stress conditions.