Fokker-Planck description of single nucleosome repositioning by dimeric chromatin remodelers.
Recent experiments have demonstrated that the ATP-utilizing chromatin assembly and remodeling factor (ACF) is a dimeric, processive motor complex which can move a nucleosome more efficiently towards longer flanking DNA than towards shorter flanking DNA strands, thereby centering an initially ill-positioned nucleosome on DNA substrates. We give a Fokker-Planck description for the repositioning process driven by transitions between internal chemical states of the remodelers. In the chemical states of ATP hydrolysis during which the repositioning takes place a power stroke is considered. The slope of the effective driving potential is directly related to ATP hydrolysis and leads to the unidirectional motion of the nucleosome-remodeler complex along the DNA strand. The Einstein force relation allows us to deduce the ATP-concentration dependence of the diffusion constant of the nucleosome-remodeler complex. We have employed our model to study the efficiency of positioning of nucleosomes as a function of the ATP sampling rate between the two motors which shows that the synchronization between the motors is crucial for the remodeling mechanism to work.
Interdisciplinary Research Institute USR 3078 CNRS and Université de Sciences et de Technologies de Lille, Parc de la Haute Borne, 50 Avenue de Halley, 59658 Villeneuve d'Ascq, France.
Yves
Y
Vandecan
Ralf
R
Blossey
D000255:Adenosine Triphosphate / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D019281:Dimerization; D008954:Models, Biological; D009707:Nucleosomes / Q000235:genetics* / Q000378:metabolism*; D011336:Probability
D009707:Nucleosomes; D000255:Adenosine Triphosphate