Conformational and Dynamic Characterization of Collagen Mimic Peptides by NMR Spectroscopy

Nuclear Magnetic Resonance (NMR) is a potent tool for exploring protein structure and dynamics, yet its application to collagen is impeded by the molecule's considerable size and rod-like configuration. To overcome this challenge, 15N/13C-isotopically selectively labeled triple helical peptides have been constructed to elucidate collagen's structural and functional intricacies. This chapter provides an in-depth examination of NMR techniques tailored to collagen mimetic peptides, encompassing a range of experiments such as triple resonance, NOESY, TOCSY, HNHA, 15N relaxation, amide proton temperature gradients, residual dipolar coupling, and diffusion studies. The characterization of the classic collagen mimetic peptide T3-785 serves as a case study, demonstrating how NMR data, including sequential and chain assignments, inter-chain NOEs, hydrogen bonding patterns, and backbone conformations, can be leveraged to derive model structures via molecular modeling techniques. Additionally, this chapter delves into NMR investigations of homotrimeric collagen mimics, focusing on collagenase cleavage sites, as well as various substitutions, and extends to heterotrimeric collagen mimics, encompassing different types of heterotrimers and peptides modeling natural interruption sites, thereby providing a comprehensive understanding of collagen's structural diversity and functional implications.