Structure and conformational cycle of a bacteriophage-encoded chaperonin.

Chaperonins are ubiquitous molecular chaperones found in all domains of life. They form ring-shaped complexes that assist in the folding of substrate proteins in an ATP-dependent reaction cycle. Key to the folding cycle is the transient encapsulation of substrate proteins by the chaperonin.

Structural features of the GroEL-GroES nano-cage required for rapid folding of encapsulated protein.

GroEL and GroES form a chaperonin nano-cage for proteins up to approximately 60 kDa to fold in isolation. Here we explored the structural features of the chaperonin cage critical for rapid folding of encapsulated substrates. Modulating the volume of the GroEL central cavity affected folding speed in accordance with confinement theory.