Spin dynamics simulation and optimal control-based pulse design. The pulse shape optimization was performed using home- written Python scripts. Numpy 25 and Scipy 26 packages were used for the linear-algebra operations, and Baysian Optimization package () was used for updating of the pulse shapes combined with GRAPE algorithm . The spin dynamics simulations, except for the calculations in Further improvement of the BE-pulses' performance, were performed using home-written Python scripts. In Further improvement of the BE-pulses' performance, SpinEvolution 20 was used. Sample preparation. Uniformly 13 C, 15 N L-alanine, L-leucine, and L-valine were purchased from Cambridge Isotope Laboratories, Inc. Uniformly 13 C, N labeled GB1-T2Q, F52Y mutant (referred to as GB1) was expressed, purified and micro-crystallized following a previously described protocol except paramagnetic labeling and its related steps . Those samples were packed into JEOL 1.0 mm MAS rotors.