Heat Shock Proteins

Hsps exist in all organisms and are highly conserved. They are also commonly known as 'stress proteins' and are divided into several families according to their molecular weights.

• 60kDa heat shock protein (Hsp60, chaperonin)
• 70kDa heat shock protein (Hsp70)
• 90kDa heat shock protein (Hsp90)
• 100kDa heat shock protein (Hsp100)

Unlike other proteins Hsps do not denature under conditions of stress as they have better hydrophobic packing, enhanced secondary protein structure, stronger hydrogen bonds and helix dipole stabilization. Instead, Hsps act to protect other cellular proteins from thermal or oxidative stress, which can cause protein unfolding, conformational changes in the protein structure and aggregation, potentially leading to a variety of pathologies. To do this, Hsps act as 'molecular chaperones' and are able to stabilize and assist in the folding of substrate proteins to the native state. Some Hsps also direct denatured proteins to the proteasome for their proteolytic destruction during the heat shock response.