Histone self-assembly

C. Self-Assembly of Histones to Form Histone Fibers. 39... 

During the course of the article, we will present evidence that the histones constitute part of a self-assembly system (Section IV). In the absence of DNA they retain the information to interact with each other to form a hierarchy of structures with dimensions, periodicities, and intermolecular contacts, compatible with what is known about the protein core of chromatin. This strongly suggests that histone-histone interactions have a fundamental role in chromatin structure. 

As noted above, salt-extracted H2A H2B will form higher oligomers, fibers could be obtained from salt-extracted histones (Fig. 3c), and even octamers are now known to associate into superstructures at very high salt concentration (Wachtel and Sperling, 1979). It would therefore seem that self-assembly is a general property of histones. The pattern of complex formation of the core histones is shown schematically in Fig. 4. 

The fact that nucleosome-like particles can be reversibly reconstituted from histones and DNA, without any additional factor, exemplifies the principle of self-assembly of biological structures. The reconstituted particles have the characteristic beaded appearance of nu-... 

The self-assembly of this fundamental building block of chromatin is a topic of enduring interest. DNase I digestion experiments as well as spectroscopic studies indicate that nucleosome core particles can be reconstituted by salt-jump (i.e., diluting NaCl concentration from 2.0 to 0.2 M) or by direct mixing of histones and DNA at the lower salt concentration. Daban and Cantor used the increase in eximer fluorescence to investigate the reassembly process in terms of a two-state model ... 

Yoshikawa, Y., Velichko, Yu. S., Ichiba, Y. and Yoshikawa, K. (2001) Self-assembled pearling structure of long duplex DNA with histone HI. Eur. J. Biochem., 268, 2593-2599. 

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