The Archaeal Exosome: Identification and Quantification of Site‐Specific Motions That Correlate with Cap and RNA Binding

Big and unexpectedly flexible: The 173 kDa exosome core is unexpectedly dynamic in solution. The kinetic and thermodynamic properties connected with the identified exchange process were quantified. Both cap protein and RNA substrate binding significantly alter the identified motions, suggesting that these interactions occur through conformational selection.