Possibility of Nonkinked Packing of DNA in Chromatin
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The idea that DNA in chromatin can be packed smoothly, without breaking of base-stacking interactions, has been explored by both energetical estimations and stereochemical model building. A model of deformed DNA is built that fits reasonably to the known dimensions of a nucleosome. The model has slightly changed torsion angles in the sugarphosphate moieties relative to B DNA, varying gradually along the chains. The angle between planes of adjacent base pairs varies between 1 and 7 degrees. This model of deformed DNA does not have any unusually close nonbonded contacts and is evidently not the only possible model of smooth packing of DNA in chromatin. An energetical estimation of the critical radius of curvature of a smoothly bent DNA molecule is made using approximate potential functions for different van der Waals contracts in the B DNA structure. The critical radius of curvature of the deformed DNA-axis is close to the radius of a nucleosome (similar to 50 A). The smooth packing is a good alternative to models of kinked folding of DNA in nucleosomes.
Sequence-dependent nucleosome nanoscale structure characterized by atomic force microscopy.
Stormberg T, Stumme-Diers M, Lyubchenko Y FASEB J. 2019; 33(10):10916-10923.
PMID: 31284760 PMC: 6766637. DOI: 10.1096/fj.201901094R.
Silberhorn E, Schwartz U, Loffler P, Schmitz S, Symelka A, De Koning-Ward T PLoS Pathog. 2016; 12(12):e1006080.
PMID: 28033404 PMC: 5198986. DOI: 10.1371/journal.ppat.1006080.
Maffeo C, Yoo J, Comer J, Wells D, Luan B, Aksimentiev A J Phys Condens Matter. 2014; 26(41):413101.
PMID: 25238560 PMC: 4207370. DOI: 10.1088/0953-8984/26/41/413101.
Kinking the double helix by bending deformation.
Du Q, Kotlyar A, Vologodskii A Nucleic Acids Res. 2007; 36(4):1120-8.
PMID: 18096619 PMC: 2275110. DOI: 10.1093/nar/gkm1125.
Sequence-dependent motions of DNA: a normal mode analysis at the base-pair level.
Matsumoto A, Olson W Biophys J. 2002; 83(1):22-41.
PMID: 12080098 PMC: 1302125. DOI: 10.1016/S0006-3495(02)75147-3.