The yeast Chd1 protein acts to position nucleosomes across genomes. Here, we model the structure of the Chd1 protein in solution and when bound to nucleosomes. In the apo state, the DNA-binding domain contacts the edge of the nucleosome while in the presence of the non-hydrolyzable ATP analog, ADP-beryllium fluoride, we observe additional interactions between the ATPase domain and the adjacent DNA gyre 1.5 helical turns from the dyad axis of symmetry. Binding in this conformation involves unravelling the outer turn of nucleosomal DNA and requires substantial reorientation of the DNA-binding domain with respect to the ATPase domains. The orientation of the DNA-binding domain is mediated by sequences in the N-terminus and mutations to this part of the protein have positive and negative effects on Chd1 activity. These observations indicate that the unfavorable alignment of C-terminal DNA-binding region in solution contributes to an auto-inhibited state.DOI: http://dx.doi.org/10.7554/eLife.22510.001

No abstract

The yeast Chd1 protein acts to position nucleosomes across genomes. Here we model the structure of the Chd1 protein in solution and when bound to nucleosomes. In the apo state the DNA binding

No abstract

The influence of particle size, cell geometry, and packing of the extraction cell was investigated for the extraction of nicotine from tobacco using supercritical CO2 modified with methanol using the hot-ball model of Bartle et al. (1990). When the tobacco was powdered to a particle size of 125−355 μm, the optimum extraction time was reduced by 15 min. Within this particle size range, particle size did not influence the recovery of nicotine so that a time-consuming sieving step is not required. The presence of water during the extraction step, which was introduced either by the packing material or by addition to the mobile phase, is important in order to desorp the nicotine from the cellulose matrix in the shortest possible time. Keywords: Supercritical fluid extraction (SFE); tobacco, nicotine