The nucleosome core particle is composed of an octamer of core histone proteins and about 146 bp of DNA. When reconstituted from purified histone octamer and defined-sequence, nucleosome positioning DNA fragments, the DNA will bind to the histone core in a number of translational phases with respect to the dyad symmetry axis of the histone octamer. Only one of these phases contains symmetrically bound DNA, and it is this species which is required for crystallization and X-ray diffraction studies. We have developed a technique for separating nucleosome core particles, containing defined-sequence 146 bp DNA, which differ only in translational phasing of the DNA with respect to the histone octamer core.
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http://dx.doi.org/10.1002/elps.11501601305 | DOI Listing |
PLoS Comput Biol
January 2025
Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang, China.
In eukaryotes, DNA achieves a highly compact structure primarily due to its winding around the histone cores. The nature wrapping of DNA around histone core form a 1.7 left-handed superhelical turns, contributing to negative supercoiling in chromatin.
View Article and Find Full Text PDFSci Rep
January 2025
Molecular Modeling and Simulation Team, Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4-9-1, Anagawa, Inage-Ku, Chiba City, Chiba, 263-8555, Japan.
Sequence-dependent mechanical properties of DNA could play essential roles in nuclear processes by affecting histone-DNA interactions. Previously, we found that the DNA entry site of the first nucleosomes from the transcription start site (+ 1 nucleosome) in budding yeast enriches AA/TT steps, but not the exit site, and the biased presence of AA/TT in the entry site was associated with the transcription levels of yeast genes. Because AA/TT is a rigid dinucleotide step, we considered that AA/TT causes DNA unwrapping.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA.
In eukaryotic nuclei, DNA is wrapped around an octamer of core histones to form nucleosomes. H1 binds to the linker DNA of nucleosome to form the chromatosome, the next structural unit of chromatin. Structural features on individual chromatosomes contribute to chromatin structure, but not fully characterized.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Biochemistry and Molecular Genetics, University of Colorado, Denver - Anschutz Medical Campus.
Organisms with smaller genomes often perform multiple functions using one multi-subunit protein complex. The Silent Information Regulator complex (SIRc) carries out all of the core functions of heterochromatin. SIR complexes first drive the initiation and spreading of histone deacetylation in an iterative manner.
View Article and Find Full Text PDFThe chromatin of the centromere provides the assembly site for the mitotic kinetochore that couples microtubule attachment and force production to chromosome movement in mitosis. The chromatin of the centromere is specified by nucleosomes containing the histone H3 variant CENP-A. The constitutive centromeric-associated network (CCAN) and kinetochore are assembled on CENP-A chromatin to enable chromosome separation.
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