Selective NMR Experiments on Macromolecules: Implementation and Analysis of QUIET-NOESY

The QUIET-NOESY experiment (Zwahlenet al., J. Am. Chem Soc.116, 362–368, 1994) is applied to measure the mobility of the flexible extensions in the large aggregate (800 kDa) of a small heat-shock protein. The proper choices of the experimental protocol and parameters are discussed in order to employ a simplified data analysis procedure. Further experimental verification of the proposed strategy is also presented using the cyclic peptide gramicidin S as a model compound. Under suitable conditions, the determinations based on the analysis of QUIET-NOESY data are affected to a negligible extent by the approximations that are introduced by the proposed approach.