6jr1
From Proteopedia
Crystal structure of the human nucleosome phased with 16 selenium atoms
Structural highlights
Function[H2B1J_HUMAN] 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.[1] [2] [3] Has broad antibacterial activity. May contribute to the formation of the functional antimicrobial barrier of the colonic epithelium, and to the bactericidal activity of amniotic fluid.[4] [5] [6] Publication Abstract from PubMedThe eukaryotic genome is compacted inside the nucleus of the cell in the form called chromatin. The fundamental unit of chromatin is the nucleosome, which contains four types of histones (H3, H4, H2A and H2B) and approximately 150 base pairs of DNA wrapped around the histone complex. The structure of the nucleosome is highly conserved across several eukaryotic species, and molecular replacement has been the primary phasing method used to solve nucleosome structures by X-ray crystallography. However, there is currently no simple, widely applicable experimental phasing method for the nucleosome. In the present study, it is demonstrated that selenomethionine-incorporated histones H3, H2A and H2B can be reconstituted into nucleosomes and crystallized for structural determination. Unexpectedly, it was found that the nucleosome can be phased with a relatively small number of Se atoms. The structures of nucleosome core particles containing 12 and 16 Se atoms were solved by SAD phasing at 2.5 and 2.4 A resolution, respectively. The present study demonstrates a simple method for determining nucleosome structures by experimental phasing, which may be particularly useful for noncanonical structures that cannot be solved by molecular replacement. Structure determination of the nucleosome core particle by selenium SAD phasing.,Saotome M, Horikoshi N, Urano K, Kujirai T, Yuzurihara H, Kurumizaka H, Kagawa W Acta Crystallogr D Struct Biol. 2019 Oct 1;75(Pt 10):930-936. doi:, 10.1107/S2059798319012713. Epub 2019 Sep 24. PMID:31588924[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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