Single-molecule tracking of sub-millisecond domain motion in calmodulin.
We used single-pair fluorescence resonance energy transfer (spFRET) to track distance changes between domains of fluorescently labeled calmodulin (CaM) on the sub-millisecond time scale. In most cases, CaM remained in the same conformational substate over time periods of up to 1 ms, showing that conformational interchange occurs on a longer time scale. However, in some instances, apparent transitions between conformational substates could be detected. The magnitude of sub-millisecond motion within the dominant conformational substate also revealed fluctuations in distance between domains that were dependent on pH and ionic strength.
Slaughter
Brian D
BD
Bieber-Urbauer
Ramona J
RJ
Johnson
Carey K
CK
D000818:Animals; D002147:Calmodulin / Q000737:chemistry*; D004058:Diffusion; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D006801:Humans; D008958:Models, Molecular; D009038:Motion; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
D002147:Calmodulin