Enhanced stability of histone octamers from plant nucleosomes: Role of H2A and H2B histones
Gel filtration and sedimentation studies have previously established that the vertebrate animal core histone octamer is in equilibrium with an (H3-H4)2 tetramer and an H2A-H2B dimer [Eickbush, T. H., & Moudrianakis, E. N. (1978) Biochemistry 17, 4955-4964; Godfrey, J. E., Eickbush, T. H., &...
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Published in | Biochemistry (Easton) Vol. 31; no. 44; pp. 10844 - 10851 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
American Chemical Society
10.11.1992
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Subjects | |
Online Access | Get full text |
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Summary: | Gel filtration and sedimentation studies have previously established that the vertebrate animal core histone octamer is in equilibrium with an (H3-H4)2 tetramer and an H2A-H2B dimer [Eickbush, T. H., & Moudrianakis, E. N. (1978) Biochemistry 17, 4955-4964; Godfrey, J. E., Eickbush, T. H., & Moudrianakis, E.N. (1980) Biochemistry 19, 1339-1346]. We have investigated the core histone octamer of wheat (Triticum aestivum L.) and have found it to be much more stable than its vertebrate animal counterpart. When vertebrate animal histone octamers are subjected to gel filtration in 2 M NaCl, a trailing peak of H2A-H2B dimer can be clearly resolved from the main octamer peak. When the plant octamer is subjected to the identical procedure, there is no trailing peak of H2A-H2B dimer, but rather a single peak containing the octamer. A sampling across the octamer peak from leading to trailing edge shows no change in the ratio of H2A-H2B to (H3-H4)2. Surprisingly, the plant octamer shows the same stability at 0.6 M NaCl, a salt concentration in which the vertebrate animal octamer dissociates into dimers and tetramers. Equilibrium sedimentation data indicate that the assembly potential of the wheat histones in 2 M NaCl is very high at all protein concentrations above 0.1 mg mL-1. In order to disrupt the forces stabilizing the plant histone octamer at high histone concentrations, the concentration of NaCl must be lowered to approximately 0.3 M. Because histones H3 and H4 are essentially identical proteins in plants and animals, it is logical to assume that the H2 histones (H2A and H2B) are responsible for the enhanced stability of plant histone octamers. Reconstitution of octamers from acid-extracted histones provides evidence that this is true. Wheat H2A and H2B histones form an octamer of enhanced stability with either wheat or chicken H3 and H4 histones. |
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Bibliography: | ark:/67375/TPS-7MS5J30V-G istex:ED308760A6018B9AF758178EB14CD1D34F71E37D ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0006-2960 1520-4995 |
DOI: | 10.1021/bi00159a027 |