Abstract

Much of structural biology to date has focused on the determination of three-dimensional models of biomolecules and the subsequent interpretation of these models to explain or better understand biological function. This is a critical first step and in many cases the pictures produced have generated invaluable insight. Yet, biological molecules such as proteins are often dynamic, with their function being modulated by exchange between different conformations. Therefore, a complete understanding of the relation between a biomolecule’s structure, dynamics and function requires the description of both the native-state conformations and all the other conformers that exchange with it. The task is, however, challenging because many of these conformers are only transiently formed and marginally populated, so that they cannot be individually characterized by most biophysical tools. Modern NMR spectroscopy provides some of the most powerful techniques for detecting and characterizing such minor states. In this talk, some of these NMR methods will be described, along with an application to the study of a cavity mutant of T4 lysozyme that binds small hydrophobic molecules and transiently populates a higher-energy state. In addition, I will show how the same methodology can be applied to characterize the highly dynamic complex of the intrinsically disordered C-terminal domain of the protein Artemis, which folds upon binding to the DNA binding domain of Ligase IV. Structural model of the complex can be obtained with no direct observation of the signals of the bound form of Artemis.