Around 40% of the human genome does not fold into stable three-dimensional structures but are either unfolded, or contain unfolded regions of significant length. The inherent flexibility of this class of proteins is essential for their function in a vast range of biomolecular process such as molecular recognition. In order to take into account the specificity of these interactions, it has been necessary to invent new approaches to study and interpret their behaviour. Nuclear magnetic resonance spectroscopy is a unique atomic resolution probe which is sensitive to a very large range of time scales. We combine experimental NMR data with a statistical model describing the energy landscape of unfolded state : the explicit ensemble description. This model is a discrete representation of the different states of theses proteins. Combining chemical shifts, residual dipolar couplings and paramagnetic relaxation enhancement, it is then possible to develop a molecular description of the unfolded state caracterising both the local and long-range information of intrinsically disordered proteins.
