In addition, we performed a detailed NMR study on the hot and cold unfolding of PAF and performed experiments to identify hidden conformations that are in slow to intermediate exchange (millisecond timescale) with the major observable form.
Residues 50 62 (labeled) experience slow timescale exchange and gradually disappear upon ZnF4 titration.
Conformational exchange on intermediate timescale within these regions broadened the majority of the NMR signals beyond detection.
This steady-state centromeric occupancy is the result of continuous dynamic exchange, on a timescale of several minutes, with a large nuclear pool of free Scm3 molecules.
Studies of the quaternary structure of the protein by cryo-electron microscopy reveal spherical assemblies between 8 and 18 nm in diameter with a central cavity (21), which undergo subunit exchange on a timescale of minutes (22).
Tracer-based methods provide the most reliable means for characterizing this short-timescale exchange.
Davey, J. A., Damry, A. M., Goto, N. K. & Chica, R. A. Rational design of proteins that exchange on functional timescales.
The lack of bootstrap support for the major branches in the largest group suggests that, despite being primarily inbreeding, there is substantial genetic exchange over longer timescales.
In water, at equilibrium, GlcNAc underwent microsecond-timescale exchange between chair puckers, in good agreement with NMR measurements and high-resolution crystallographic data for protein-bound GlcNAc ligands, where an appreciable number are not C1 conformers.
Importantly, the predicted microsecond-timescale exchange between GlcNAc chair puckers was not in disagreement with NMR measurements reported here (Table I) and elsewhere (Mulloy and Johnson 1987; Jin et al. 2009).
