Speeding up sequence specific assignment of IDPs
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The characterization of intrinsically disordered proteins (IDPs) by NMR spectroscopy is made difficult by the extensive spectral overlaps. To overcome the intrinsic low-resolution of the spectra the introduction of high-dimensionality experiments is essential. We present here a set of high-resolution experiments based on direct 13C-detection which proved useful in the assignment of α-synuclein, a paradigmatic IDP. In particular, we describe the implementation of 4D HCBCACON, HCCCON, HCBCANCO, 4/5D HNCACON and HNCANCO and 3/4D HCANCACO experiments, specifically tailored for spin system identification and backbone resonances sequential assignment. The use of non-uniform-sampling in the indirect dimension and of the H-flip approach to achieve longitudinal relaxation enhancement rendered the experiments very practical.
KeywordsIntrinsically disordered proteins 13C detection Non-uniform sampling Multidimensional NMR experiment Backbone assignment Spin system identification
This work has been supported in part by the EC 7th Framework program BioNMR, contract 261863 and by the EC Marie Curie ITN program (IDPbyNMR, contract 264257).
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