“…These techniques facilitate the NMR analyses of large proteins because the partial labeling of the molecule prevents signal overlap on the obtained spectra while still enabling the study of the structure of the domains in their natural surroundings within a multi-subunit molecule [3,4]. Various large multi-domain enzymes, e.g., ␣-amylases, -keratinases, or cellulases, are of a great interest because they can be efficiently used in industry [5][6][7]. Thus, structural studies of such enzymes in solution, e.g., via NMR, are crucial for a better understanding of the key mechanisms and processes of substrate recognition.…”