Allahverdi A, Yang R, Korolev N, Fan Y, Davey CA, Liu CF, Nordenskiöld L. The effects of histone H4 tail acetylations on cation-induced chromatin folding and self-association.
Nucleic Acids Res 2010;
39:1680-91. [PMID:
21047799 PMCID:
PMC3061077 DOI:
10.1093/nar/gkq900]
[Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Understanding the molecular mechanisms behind regulation of chromatin folding through covalent modifications of the histone N-terminal tails is hampered by a lack of accessible chromatin containing precisely modified histones. We study the internal folding and intermolecular self-association of a chromatin system consisting of saturated 12-mer nucleosome arrays containing various combinations of completely acetylated lysines at positions 5, 8, 12 and 16 of histone H4, induced by the cations Na+, K+, Mg2+, Ca2+, cobalt-hexammine3+, spermidine3+ and spermine4+. Histones were prepared using a novel semi-synthetic approach with native chemical ligation. Acetylation of H4-K16, but not its glutamine mutation, drastically reduces cation-induced folding of the array. Neither acetylations nor mutations of all the sites K5, K8 and K12 can induce a similar degree of array unfolding. The ubiquitous K+, (as well as Rb+ and Cs+) showed an unfolding effect on unmodified arrays almost similar to that of H4-K16 acetylation. We propose that K+ (and Rb+/Cs+) binding to a site on the H2B histone (R96-L99) disrupts H4K16 ε-amino group binding to this specific site, thereby deranging H4 tail-mediated nucleosome–nucleosome stacking and that a similar mechanism operates in the case of H4-K16 acetylation. Inter-array self-association follows electrostatic behavior and is largely insensitive to the position or nature of the H4 tail charge modification.
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