ATPase cycle controls the conformation of an archaeal chaperonin as visualized by cryo-electron microscopy

AbstractChaperonins are double-ring protein folding machines fueled by ATP binding and hydrolysis. Conformational rearrangements upon ATPase cycling of the group I chaperonins, typified by the Escherichia coli GroEL/GroES system, have been thoroughly investigated by cryo-electron microscopy and X-ray crystallography. For archaeal group II chaperonins, however, these methods have so far failed to provide a correlation between the structural and the functional states. Here, we show that the conformation of the native αβ-thermosome of Thermoplasma acidophilum in vitrified ice is strictly regulated by adenine nucleotides