title: Circadian clock parameter measurement: characterization of clock transcription factors using surface plasmon resonance.
abstract: To refine mathematical models of the transcriptional/translational feedback loop in the clockwork of Arabidopsis thaliana, the investigators sought to determine the affinity of the transcription factors LHY, CCA1, and CHE for their cognate DNA target sequences in vitro. Steady-state dissociation constants were observed to lie in the low nanomolar range. Furthermore, the data suggest that the LHY/CCA1 heterodimer binds more tightly than either homodimer and that DNA binding of these complexes is temperature compensated. Finally, it was found that LHY binding to the evening element in vitro is enhanced by both molecular crowding effects and by casein kinase 2-mediated phosphorylation.
authors: Department of Clinical Neurosciences, University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
authors: John S
authors: JS
authors: O'Neill
authors: Gerben
authors: G
authors: van Ooijen
authors: Thierry
authors: T
authors: Le Bihan
authors: Andrew J
authors: AJ
authors: Millar
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D047390:Casein Kinase II / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C113192:LHY protein, Arabidopsis; D014157:Transcription Factors; D047390:Casein Kinase II