Biomolecular NMR Assignment: Illustration Using the Heme Signals in Horse Cytochrome C

NMR spectroscopy is a powerful technique with applications in a myriad of areas of scientific research. In (bio)chemical research, NMR spectroscopy can provide unique insights on structure, dynamics, and reactivity of target molecules. These studies typically start with the assignment of the NMR signals to specific nuclei. Here, we describe an NMR assignment activity aimed at advanced undergraduate or graduate level students in either the biological or chemical sciences. Using a variety of NMR spectral data, students assigned the protons of the horse cytochrome c heme cofactor in a single 4 h session. It provides students with the opportunity to execute successfully a simulated research task and appreciate the complexity and challenges of an NMR assignment and the excitement of finding the solution. For instructors, it is designed to dispense the need to access NMR spectrometers, which facilitates its implementation. Ultimately, this increases the range of institutions and curricular units where it can be adopted.