5onw
From Proteopedia
X-Ray crystal structure of a nucleosome core particle with its DNA site-specifically crosslinked to the histone octamer and the two H2A/H2B dimers crosslinked via H2A N38C
Structural highlights
FunctionH32_XENLA Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Publication Abstract from PubMedWe engineered nucleosome core particles (NCPs) with two site-specific cysteine crosslinks that increase the stability of the particle. The first disulfide was introduced between the two copies of H2A via a H2A-N38C point mutation, effectively crosslinking the two H2A/H2B heterodimers together to stabilize the histone octamer against H2A/H2B dimer dissociation. The second crosslink was engineered between a R40C point mutation on the N-terminal tail of H3 and the NCP DNA ends by the introduction of a convertible nucleotide. This crosslink maintains the nucleosome DNA in a fixed translational setting relative to the histone octamer and prevents dilution-driven dissociation. The X-ray crystal structures of NCPs containing the disulfides in isolation and in combination were determined. Both disulfides stabilize the structure of the nucleosome core particle without disturbing the overall structure. Nucleosomes containing these modifications will be advantageous for biochemical and structural studies as a consequence of their greater resistance to dissociation during high dilution in purification, elevated salt for crystallization and vitrification for cryo-EM. Site-Specific Disulfide Crosslinked Nucleosomes with Enhanced Stability.,Frouws TD, Barth PD, Richmond TJ J Mol Biol. 2017 Nov 4. pii: S0022-2836(17)30522-3. doi:, 10.1016/j.jmb.2017.10.029. PMID:29113904[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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