BEST-TROSY experiments for time-efficient sequential resonance assignment of large disordered proteins
The characterization of the conformational properties of intrinsically disordered proteins (IDPs), and their interaction modes with physiological partners has recently become a major research topic for understanding biological function on the molecular level. Although multidimensional NMR spectroscopy is the technique of choice for the study of IDPs at atomic resolution, the intrinsically low resolution, and the large peak intensity variations often observed in NMR spectra of IDPs call for resolution- and sensitivity-optimized pulse schemes. We present here a set of amide proton-detected 3D BEST-TROSY correlation experiments that yield the required sensitivity and spectral resolution for time-efficient sequential resonance assignment of large IDPs. In addition, we introduce two proline-edited 2D experiments that allow unambiguous identification of residues adjacent to proline that is one of the most abundant amino acids in IDPs. The performance of these experiments, and the advantages of BEST-TROSY pulse schemes are discussed and illustrated for two IDPs of similar length (~270 residues) but with different conformational sampling properties.
KeywordsBEST TROSY IDP Viral protein Amino-acid-type editing Longitudinal-relaxation enhancement
We are grateful to Isabel Ayala and Adrien Favier for help in protein production and technical support. This work has been supported by grants from the European Commission (FP7-ITN IDPbyNMR contract No. 264257 and FP7-I3 BIO-NMR contract No. 261863), from the DFG (SFB974, A11), and from the Austrian Science Foundation FWF (W1221-B03 and P 20549-N19).
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