Detection of interaction constants between biological clock proteins by Surface Plasmon Resonance

Abstract

Organisms adopt their behaviors and physiology to the appropriate time of the day to anticipate daily environmental changes and the circadian clock regulates their daily rhythms. In mammals, the clock is present in essentially every cell. A heterodimer of CLOCK and BMAL1 proteins binds to the E-box in Per and Cry promoters and activates their transcription. In this work, we have purified core clock proteins and characterized the affinity of previously identified clock-relevant transcription factors. We have investigated the mechanism of the clock complex and the interactions of clock proteins with and without DNA using Surface Plasmon Resonance (SPR). Kinetic parameters determined from real time data bring a solid insight into the interactions of the clock proteins with their cognate promoter.