CBFbeta allosterically regulates the Runx1 Runt domain via a dynamic conformational equilibrium.
Core binding factors (CBFs) are heterodimeric transcription factors consisting of a DNA-binding CBFalpha subunit and non-DNA-binding CBFbeta subunit. The CBFbeta subunit increases the affinity of the DNA-binding Runt domain of CBFalpha for DNA while making no direct contacts to the DNA. We present evidence for conformational exchange in the S-switch region in a Runt domain-DNA complex that is quenched upon CBFbeta binding. Analysis of (15)N backbone relaxation parameters shows that binding of CBFbeta reduces the backbone dynamics in the microsecond-to-millisecond time frame for several regions of the Runt domain that make energetically important contacts with the DNA. The DNA also undergoes conformational exchange in the Runt domain-DNA complex that is quenched in the presence of CBFbeta. Our results indicate that allosteric regulation by the CBFbeta subunit is mediated by a shift in an existing dynamic conformational equilibrium of both the Runt domain and DNA.
Yan
Jiangli
J
Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22906, USA.
Liu
Yizhou
Y
Lukasik
Stephen M
SM
Speck
Nancy A
NA
Bushweller
John H
JH
D000495:Allosteric Site; D001665:Binding Sites; D002151:Calorimetry; D050676:Core Binding Factor Alpha 2 Subunit; D004247:DNA / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry*; D019281:Dimerization; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000737:chemistry*; D013997:Time Factors; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000737:chemistry*
D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D004247:DNA; D009584:Nitrogen