Could there be a repair mechanism in the human body more remarkable than that of chaperonins, which help misfolded proteins to refold themselves properly? Recent collaborative work by two leading chaperonin researchers has fitted what is known of the structure of a particular such enzyme to a model of its action.1 The result is a wonder to behold.
If a protein's amino acid chain fails to fold into its proper or native three-dimensional shape, other proteins can attach to it, creating clumps that threaten the ability of the cell to function. In the bacterium Escherichia coli, a chaperonin called GroEL helps to prevent this. It comprises two large rings, each of which has seven protein subunits that bind adenosine triphosphate (ATP), providing the molecular engine's power. It also is lined with residues that can become hydrophobic, or water-avoiding, enabling binding to a misfolded protein, which leaves some of its own ...
