Site-specific acetylation of HMGN1 within the nucleosome binding domain Medine Soydan, and Anne C. Conibear Institute of Applied Synthetic Chemistry, Faculty of Technical Chemistry, TU Wien, Vienna, Austria Email: medine.soydan@tuwien.ac.at Chromatin is a complex of RNA, DNA, and proteins to store the genome of eukaryotes in physiological conditions and to organize DNA metabolic pathways. DNA replication, transcription, recombination, and chromosome segregation are the major biological processes that chromatin is involved in. Nucleosomes are the repeating units in chromatin structure, and can undergo certain modifications. Several regulatory proteins, including non-histone proteins like HMGN1, can participate in chromatin structure modification and may result in functional change. HMGN1 is subjected intensely to posttranslational modifications (PTMs), mainly lysine acetylation and serine phosphorylation. Although various biological functions are attributed to HMGN1 and its PTMs, the precise effects of its PTMs on the biological function remain largely unknown. We aim to investigate the effects of lysine acetylation in the nucleosome binding domain of HMGN1 on interactions of HMGN1 with nucleosomes. We present the synthesis of site-specifically acetylated HMGN1 variants by a semi-synthetic approach. We performed structural analysis of the site-specifically acetylated HMGN1 variants by CD spectroscopy, which shows that both unmodified and acetylated variants of HMGN1 are intrinsically disordered, as reported in the literature. We also conducted preliminary thermal stability shift assays to examine the interactions of HMGN1 variants with nucleosomes. We anticipate the assays will provide more insights on how HMGN1 accomplishes specific functions within the cells due to PTMs at precise positions.