Bavykin S G, Usachenko S I, Shik V V, Beliavskiĭ A V, Lishanskaia I A
Mol Biol (Mosk). 1985 Jan-Feb;19(1):144-61.
A refined high-resolution map for the linear arrangement of histones along DNA in the nucleosomal core particles has been determined by DNA-protein crosslinking. Histones are aligned on one strand of the 145 bp core DNA in the following order: (5') H2B25,35--H455,65--H375,85,, 95/H488--H2B105, 115--H2A118--H3135, 145/H2A145 (3') (the subscripts indicate the approximate distance in nucleotides of the main histone binding sites from the 5'-end of the core DNA). This suggests a symmetrical and rather autonomous arrangement of the histone tetramer (H3, H4)2 and two dimers (H2A, H2B) on the double-stranded core DNA: H2A/H3--(H2A, H2B)--(H3, H4)2--(H2B, H2A)--H3/H2A. The arrangement of histones on DNA was found to be very similar for the cores isolated from the repressed nuclei of sea urchin sperm and chicken erythrocytes and from the active in transcription and replication Drosophila embryo and yeast nuclei. This indicates that the core nucleosome structure is highly conserved through evolution and that the overall inactivation of chromatin does not affect the primary organization of the cores. A new binding site H2B58 was found for a sea urchin spermal variant of H2B which contains an additional basic segment within the N-terminal part of the molecule. The core isolation procedure was shown to introduce changes into the core structure which are reflected in the appearance of a new binding site H2A75.
通过DNA - 蛋白质交联，已确定了核小体核心颗粒中组蛋白沿DNA线性排列的精细高分辨率图谱。组蛋白在145 bp核心DNA的一条链上按以下顺序排列：(5') H2B25,35--H455,65--H375,85,, 95/H488--H2B105, 115--H2A118--H3135, 145/H2A145 (3')（下标表示主要组蛋白结合位点距核心DNA 5'端的核苷酸大致距离）。这表明组蛋白四聚体(H3, H4)2和两个二聚体(H2A, H2B)在双链核心DNA上呈对称且相当自主的排列：H2A/H3--(H2A, H2B)--(H3, H4)2--(H2B, H2A)--H3/H2A。从海胆精子和鸡红细胞的抑制核以及转录和复制活跃的果蝇胚胎和酵母核中分离出的核心，其DNA上组蛋白的排列非常相似。这表明核心核小体结构在进化过程中高度保守，并且染色质的整体失活不会影响核心的初级组织。发现了海胆精子中H2B变体的一个新结合位点H2B58，该变体在分子的N端部分含有一个额外的碱性片段。核心分离程序显示会导致核心结构发生变化，这反映在新结合位点H2A75的出现上。
