title: High-resolution structure of the native histone octamer.
abstract: Crystals of native histone octamers (H2A-H2B)-(H4-H3)-(H3'-H4')-(H2B'-H2A') from chick erythrocytes in 2 M KCl, 1.35 M potassium phosphate pH 6.9 diffract X-rays to 1.90 A resolution, yielding a structure with an R(work) value of 18.7% and an Rfree of 22.2%. The crystal space group is P6(5), the asymmetric unit of which contains one complete octamer. This high-resolution model of the histone-core octamer allows further insight into intermolecular interactions, including water molecules, that dock the histone dimers to the tetramer in the nucleosome-core particle and have relevance to nucleosome remodelling. The three key areas analysed are the H2A'-H3-H4 molecular cluster (also H2A-H3'-H4'), the H4-H2B' interaction (also H4'-H2B) and the H2A'-H4 beta-sheet interaction (also H2A-H4'). The latter of these three regions is important to nucleosome remodelling by RNA polymerase II, as it is shown to be a likely core-histone binding site, and its disruption creates an instability in the nucleosome-core particle. A majority of the water molecules in the high-resolution octamer have positions that correlate to similar positions in the high-resolution nucleosome-core particle structure, suggesting that the high-resolution octamer model can be used for comparative studies with the high-resolution nucleosome-core particle.
authors.affiliation: School of Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, England. c.m.wood@livjm.ac.uk
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Wood
authors.forename: James M
authors.initials: JM
authors.lastname: Nicholson
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Lambert
authors.forename: Laurent
authors.initials: L
authors.lastname: Chantalat
authors.forename: Colin D
authors.initials: CD
authors.lastname: Reynolds
authors.forename: John P
authors.initials: JP
authors.lastname: Baldwin
mesh_terms: D000818:Animals; D002645:Chickens; D018360:Crystallography, X-Ray; D019281:Dimerization; D004912:Erythrocytes / Q000737:chemistry; D006657:Histones / Q000737:chemistry*; D015394:Molecular Structure; D009707:Nucleosomes / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D014867:Water / Q000737:chemistry
chemical_list: D006657:Histones; D009707:Nucleosomes; D014867:Water