Conformational Dynamics in NF-κB Transcriptional Regulation

The NF-κB family of transcription factor is a central mediator immune and imflammatory responses. functions as dimer recognize DNA through the two N-terminal domains (NTDs). Previous hydrogen-deuterium exchange mass spectrometry, stopped-flow experiments molecular dynamics simulations suggested NTDs can undergo relative motions which plays an important role in kinetics association dissociation. Here we showed by single-molecule FRET direct evidence domain RelA-p50 dimer. Surprisingly, underwent slow heterogeneous on timescale seconds to minutes. These are scaled down when bound allosterically altered inhibitor protein IκBα, known accelerate dissociation prevent binding. A new DNA-bound conformation unexpected from crystal structure was also observed. Together, our results provide visualization quantitative characterization large-scale shed light understanding protein-protein interactions.