AMSBIO announced the addition of new biotinylated histones and nucleosomes to its expanding range of recombinant nucleosomes, purified nucleosomes and full length histone proteins. A nucleosome is the basic unit of DNA packaging. It consists of a segment of DNA wound around a core (“octamer”) of 8 histone proteins (two each of histones H2A, H2B, H3, and H4). The “tails” of these histone proteins stick out, where they can be modified by a number of different histone acetyltransferases, methyltransferases, PARPs, and other epigenetic enzymes. Many of these enzymes modify very specific sites e.g. EZH2, specifically tri-methylates the lysine at position 27 in the H3 histone. AMSBIO's new line of biotinylated histone peptides have been developed for enzyme kinetic studies as well as for screening small molecular inhibitors of different histone methyltransferases in drug discovery and HTS applications. The major difference between AMSBIO recombinant nucleosomes made in E. coli and those purified from whole cells is that the recombinant ones are unmodified. E. coli and other bacteria do not have the enzymes to methylate or acetylate the histone proteins. AMSBIO nucleosomes purified from mammalian cells are supplied methylated or acetylated on most histone sites, making them suitable substrates for demethylases.

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