Chaperone‐like activity and hydrophobicity of α‐crystallin

α‐Crystallin, a prominent member of small heat shock protein (sHsp) family and a major structural protein of the eye lens is a large polydisperse oligomer of two isoforms, αA‐ and αB‐crystallins. Numerous studies have demonstrated that α‐crystallin functions like a molecular chaperone in preventing the aggregation of various proteins under a wide range of stress conditions. The molecular chaperone function of α‐crystallin is thus considered to be vital in the maintenance of lens transparency and in cataract prevention. α‐Crystallin selectively interacts with non‐native proteins thereby preventing them from aggregation and helps maintain them in a folding competent state. It has been proposed and generally accepted that α‐crystallin suppresses the aggregation of other proteins through the interaction between hydrophobic patches on its surface and exposed hydrophobic sites of partially unfolded substrate protein. However, a quantifiable relationship between hydrophobicity and chaperone‐like activity remains a matter to be concerned about. On an attentive review of studies on α‐crystallin chaperone‐like activity, particularly the studies that have direct or indirect implications to hydrophobicity and chaperone‐like activity, we found several instances wherein the correlation between hydrophobicity and its chaperone‐like activity is paradoxical. We thus attempted to provide an overview on the role of hydrophobicity in chaperone‐like activity of α‐crystallin, the kind of evaluation done for the first time.iubmb Life, 58: 632 ‐ 641, 2006