Integrating spatiotemporal features of a ligand-regulated, multi-state allosteric protein

Dynamic protein molecules are defined by their spatiotemporal characteristics and should thus be represented by models incoporating both characteritics. Structural biology enables determination of atomic structures of individual conformational states of a given protein. Obtaining the complementary temporal information of a given time resolution, which can be directly linked to the corresponding atomic structures, requires identifying at each time point the specific conformational state adopted by the protein. Here, we examine individual regulator of conductance to K⁺ (RCK) domains in the regulatory module of the MthK channel by monitoring in real time the orientation of an α-helix that is conformational-state-specific. The acquired dynamic information that specifies an RCK domain's multi-state conformational changes, combined with already available corresponding atomic structures, enables us to establish an experiment-based spatiotemporal representation of an RCK domain, and to deduce a quantitative mechanistic model of the channel.