Poster abstracts

Poster number 10 submitted by John Shimko

Total synthesis of histone H3 acetylated at lysine 56

John C. Shimko (Ohio State Biochemistry Program, OSU), Tiffany V. Sommers (Department of Chemistry, OSU), Jennifer J. Ottesen (Department of Biochemistry, OSU)

Abstract:
The eukaryotic genome is organized by the periodic wrapping of the DNA double helix around histone octamers to form nucleosomes. The DNA entry-exit region of the nucleosome is a vital interface between the DNA double helix and the histone octamer. Dynamic acetylation of histone H3 lysine 56, buried beneath the DNA in the entry-exit region, plays an important role in DNA repair and transcription regulation. Acetylation of H3-K56 is proposed to lower the affinity of the protein core for the DNA resulting in observable changes in nucleosome stability and structure. To test this hypothesis, we are employing sequential native chemical ligation to generate full-length histone H3 acetylated at K56 (H3-K56Ac). The chemoselective combination of three synthetic peptide segments allows for the site specific introduction of an acetylated lysine at H3 residue 56. Nucleosomes will be reconstituted with the synthetic, chemically modified H3-K56Ac along with recombinant histones H2A, H2B, and H4 and DNA. Biochemical and biophysical study of generated semi-synthetic, modified nucleosomes will allow for the direct characterization of the effects of H3-K56Ac on nucleosome stability and structure.

Keywords: histone, synthesis, ligation