The microtubule dynamics in the neuronal cells is mainly modulated by two members of the structural MAPs, MAP2 and tau, which play fundamental roles in the development of dendrites and axons. The MAP2 proteins are present mainly in the dendrites of neuronal cells, while tau is present in axons.
MAP2c is a 49 kDa intrinsically disordered protein (IDP). IDPs are macromolecules interesting both from biophysical and physiological point of view, but difficult to study by the current biophysical methods. Nuclear magnetic resonance (NMR) is a key technique for atomic-resolution studies of IDPs, but its applicability is limited by a spectral overlap in case of long or highly repetitive amino-acid sequences. Our group developed high-resolution NMR methodology that overcomes this limitation and makes studies of large IDPs possible.
We present an atomic-resolution conformational analysis of MAP2c based on chemical shifts obtained from 5D NMR experiments, paramagnetic relaxation enhancement providing information about intramolecular distances, and small angle x-ray scattering experiments reflecting the overall size and shape of the MAP2c molecule in solution. Ensembles of structures of phosphorylated and nonphosphorylated MAP2c reproducing the experimental data were selected by the program ASTEROIDS. The ensembles were used to evaluate local conformation and long-range contacts in the MAP2c molecule.