Faculty Collaboration Database

Acetylation of H4 suppresses the repressive effects of the N-termini of histones H3/H4 and facilitates the formation of positively coiled DNA. Biochemistry 2008 Jul 08;47(27):7053-65

Date

06/12/2008

Pubmed ID

18543948

DOI

10.1021/bi8004945

Scopus ID

2-s2.0-46849090491 (requires institutional sign-in at Scopus site)   3 Citations

Abstract

We have studied the role of the N-termini of histones H3/H4 in the regulation of the conformational changes that occur in H3/H4 during their deposition on DNA by NAP1 (nucleosome assembly protein 1). Removal of the N-termini extensively increased the right-handed conformation of H3/H4 as assayed by the increased levels of positive coils that were formed on DNA. The osmolytes, TMAO, betaine, sarcosine, alanine, glycine, and proline to varying degrees, facilitated the formation of positive coils. The denaturant, urea (0.6 M), blocked the osmolyte effects, causing a preference of H3/H4 to form negative coils (the left-handed conformation). Acetylated H3/H4 also formed high levels of positive coils, and it is proposed that both the osmolytes and acetylation promote the formation of an alpha-helix in the N-termini. This structural change may ultimately explain a unique feature of transcription through nucleosomes, i.e., that H2A/H2B tends to be more mobile than H3/H4. By using combinations of H3 and H4 that were either acetylated or the N-termini removed, it was also determined that the N-terminus of H4 is primarily responsible for repressing the formation of positive coils. Additional gradient analyses indicate that NAP1 establishes an equilibrium with the H3/H4-DNA complexes. This equilibrium facilitates a histone saturation of the DNA, a unique state that promotes the right-handed conformation. NAP1 persists in the binding of the complexes through interaction with the N-terminus of H3, which may be a mechanism for subsequent remodeling of the nucleosome during transcription and replication.

Author List

Peterson S, Jackson V

Author

Vaughn Jackson PhD Emeritus Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acetylation
Animals
Cell Cycle Proteins
Chickens
DNA, Superhelical
Electrophoresis
Glycine
Histones
Nuclear Proteins
Nucleic Acid Conformation
Nucleosome Assembly Protein 1
Protein Binding
Protein Structure, Secondary
Repressor Proteins
Sequence Deletion
Solubility