通过荧光能量转移和扫描力显微镜研究三核小体压缩。

Trinucleosome compaction studied by fluorescence energy transfer and scanning force microscopy.

作者信息

Bussiek Malte, Tóth Katalin, Schwarz Nathalie, Langowski Jörg

机构信息

Division of Biophysics and Macromolecules, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 580, TP3, D-69120 Heidelberg, Germany.

出版信息

Biochemistry. 2006 Sep 12;45(36):10838-46. doi: 10.1021/bi060807p.

DOI:10.1021/bi060807p

PMID:16953569

Abstract

The effect of the salt concentration, linker histone H1, and histone acetylation on the structure of trinucleosomes reconstituted on a 608 bp DNA containing one centered nucleosome positioning signal was studied. Fluorescence resonance energy transfer (FRET) in solution and scanning force microscopy (SFM) measurements in liquid were done on the same samples. The distance between the DNA ends decreases under the effect of an increasing salt concentration and also by the incorporation of the H1 linker histone. A decrease of internucleosomal center-to-center (cc) distances by H1 was observed that was limited to a minimal value of about 20 nm. The distribution of the angle formed between consecutive nucleosomes was narrowed by H1. The effect of acetylation of all histones leads to decompaction, measured as an increased distance between the DNA ends, and also increased the internucleosomal distances. Selective acetylation of histone H4, however, compacts the structure as measured by FRET.

摘要

研究了盐浓度、连接组蛋白H1和组蛋白乙酰化对在含有一个中心核小体定位信号的608 bp DNA上重构的三核小体结构的影响。对相同样品进行了溶液中的荧光共振能量转移（FRET）和液体中的扫描力显微镜（SFM）测量。在盐浓度增加以及掺入H1连接组蛋白的作用下，DNA末端之间的距离减小。观察到H1使核小体中心到中心（cc）的距离减小，其最小值约为20 nm。H1使连续核小体之间形成的角度分布变窄。所有组蛋白乙酰化的作用导致结构松弛，表现为DNA末端之间的距离增加，同时也增加了核小体间的距离。然而，通过FRET测量，组蛋白H4的选择性乙酰化使结构紧凑。