Conformational Dynamics of Proteins from Microseconds to Milliseconds by NMR: Implications for Molecular Recognition

Nuclear Magnetic Resonance (NMR) spectroscopy enables the non-invasive resolution of biomolecular structures, ranging from globular proteins to intrinsically disordered proteins (IDPs). NMR allows the monitoring of equilibrium kinetics under various conditions and timescales, spanning from picoseconds to days. Structural interconversion kinetics are typically qualitatively assessed by linewidth analysis in NMR spectra and quantitatively by longitudinal and transverse relaxation experiments and relaxation dispersion experiments. However, due to experimental limitations, conformational changes occurring between the rotational correlation time of proteins (typically between 4-200 ns) and 250 μs remained elusive. Such atomic motions are crucial for protein-protein interactions and interactions with other molecules, creating a kinetic gap in NMR experiments. By combining advancements in NMR spectrometer electronics, novel data acquisition methods and theoretical treatment of the data, we successfully reduced the lower limit of conformational kinetic characterization from ~250 μs to ~4 μs. In this seminar, we will present our latest technical developments that enabled access to the structural interconversion in different time scales. Furthermore, we will showcase the application of these methodological innovations in three distinct projects: i) exploring the role of conformational dynamics of human troponin C in cardiomyopathy development; ii) investigating the conformational dynamics of ubiquitin in high-viscosity environments; and iii) unraveling the modulation of stability, aggregation, and substrate recognition of the enzyme Tetracenomicin aromatase/cyclase (TcmN). These studies shed light on the intricate relationship between protein dynamics and biological function.
This work was supported by CNPq, FAPEMIG, and CAPES. Further acknowledgments: Laboratório de Ressonância Magnética Nuclear de Alta Resolução da UFMG – LAREMAR.