A six-dimensional alpha proton detection-based APSY experiment for backbone assignment of intrinsically disordered proteins

Sequence specific resonance assignment is the prerequisite for the NMR-based analysis of the conformational ensembles and their underlying dynamics of intrinsically disordered proteins. However, rapid solvent exchange in intrinsically disordered proteins often complicates assignment strategies based on HN-detection. Here we present a six-dimensional alpha proton detection-based automated projection spectroscopy (APSY) experiment for backbone assignment of intrinsically disordered proteins. The 6D HCACONCAH APSY correlates the six different chemical shifts, H-alpha(i - 1), C-alpha(i - 1), C'(i - 1), N(i), C-alpha(i) and H-alpha(i). Application to two intrinsically disordered proteins, 140-residue alpha-synuclein and a 352-residue isoform of Tau, demonstrates that the chemical shift information provided by the 6D HCACONCAH APSY allows efficient backbone resonance assignment of intrinsically disordered proteins.