Using relaxation dispersion NMR spectroscopy to determine structures of excited, invisible protein states
Currently the main focus of structural biology is the determination of static three-dimensional representations of biomolecules that for the most part correspond to low energy (ground state) conformations. However, it is becoming increasingly well recognized that higher energy structures often play important roles in function as well. Because these conformers are populated to only low levels and are often only transiently formed their study is not amenable to many of the tools of structural biology. In this perspective we discuss the role of CPMG-based relaxation dispersion NMR spectroscopy in characterizing these low populated, invisible states. It is shown that robust methods for measuring both backbone chemical shifts and residual anisotropic interactions in the excited state are in place and that these data provide valuable restraints for structural studies of invisible conformers.
KeywordsExcited State Dipolar Coupling Chemical Exchange Relaxation Dispersion Backbone Dynamic
This work was supported by a grant from the Canadian Institutes of Health Research (CIHR). D.F.H. and P.V. hold post-doctoral fellowships from the CIHR and the CIHR Training Grant on Protein Folding in Health and Disease, respectively.
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