Protein dynamics, or the molecular motions of proteins, can play a significant role in controlling protein stability and function. In particular, motions on fast time scales (picoseconds to nanoseconds) have the potential to influence thermal stability, ligand-binding, catalysis, allosteric regulation, etc. Fast time scale dynamics can be investigated by using 2D nuclear magnetic resonance (NMR) techniques to measure the magnetic relaxation of nuclei within isotopically-labeled protein samples. Measured relaxation parameters can be related to the motional properties of the atoms in the protein. Consequently, comparison of NMR data for related proteins can provide insights into the role of dynamics in protein function and stability. This dissertation describes a series of experimental studies of protein dynamics aimed at furthering understanding of fast time scale motions in proteins by examining the influence of structural modifications or binding on the dynamics of a protein, both in the vicinity of the modified site and more distal from this site. These studies include: (1) examination of the influence of a single guest amino acid on the dynamics of an entire protein, the B1 domain of protein G (GB1); (2) investigation of the influence of secondary structural context on the dynamics of a “chameleon” peptide sequence in α-helix and β-hairpin conformations within GB1; (3) examination of the influence of protein repeat structure on protein dynamics using designed proteins containing two or three consensus tetratricopeptide repeats, CTPR2 and CTPR3, respectively; (4) investigation of the influence of conserved packing interactions on dynamics through a comparison of the dynamics of a natural protein, VpU-binding protein, with that of a consensus-based designed protein, CTPR3; and (5) examination of the influence of peptide-binding on the dynamics of the phosphotyrosine binding domain of insulin receptor substrate 1.