Weak and Transient Protein Interactions Determined by Solid-State NMR

Despite their roles in controlling many cellular

processes, weak and transient interactions between large

structured macromolecules and disordered protein segments

cannot currently be characterized at atomic resolution by Xray

crystallography or solution NMR. Solid-state NMR does

not suffer from the molecular size limitations affecting solution

NMR, and it can be applied to molecules in different

aggregation states, including non-crystalline precipitates and

sediments. A solid-state NMR approach based on high

magnetic fields, fast magic-angle sample spinning, and deuteration

provides chemical-shift and relaxation mapping that

enabled the characterization of the structure and dynamics of

the transient association between two regions in an 80 kDa

protein assembly. This led to direct verification ofamechanism

of regulation of E. coli DNA metabolism