Expression and purification of recombinant yeast Ada2/Ada3/Gcn5 and Piccolo NuA4 histone acetyltransferase complexes. Journal   Methods (San Diego, Calif.) Citation   Methods. 41(3):271-7 Publication date   2007 Mar Authors   Barrios A Selleck W Hnatkovich B Kramer R Sermwittayawong D Tan S Investigators   Song Tan Grant agencies   National Institute of General Medical Sciences Grants   NIGMS GM060489 NIGMS R01 GM060489-01 NIGMS R01 GM060489-02 NIGMS R01 GM060489-03 NIGMS R01 GM060489-04 NIGMS R01 GM060489-05 MeSH headings   Chromatography, Affinity Cloning, Molecular Saccharomyces cerevisiae Proteins Transcription Factors MeSH qualifiers   methods genetics isolation & purification Abstract   Acetylation of histone tails by histone acetyltransferase (HAT) enzymes is a key post-translational modification of histones associated with transcriptionally active genes. Acetylation of the physiological nucleosome substrate is performed in cells by megadalton complexes such as SAGA and NuA4. To understand how HAT enzymes specifically recognize their nucleosome and not just histone tail substrates, we have identified the catalytic SAGA and NuA4 subcomplexes sufficient to act on nucleosomes. We describe here expression and purification procedures to prepare recombinant yeast Ada2/Ada3/Gcn5 subcomplex of SAGA which acetylates histones H3 and H2B on nucleosomes, and the Piccolo NuA4 complex which acetylates histones H4 and H2A on nucleosomes. We demonstrate an unexpected benefit of using the BL21-CodonPlus strain to enhance the purity of metal affinity purified Ada2/Ada3/Gcn5 complex. We also identify Escherichia coli EF-Tu as a contaminant that copurifies with both complexes over multiple chromatographic steps and use of hydrophobic interaction chromatography to remove the contaminant from the Piccolo NuA4 complex. The methods described here will be useful for studies into the molecular mechanism of these enzymes and for preparing the enzymes as reagents to study the interplay of nucleosome acetylation with other chromatin modification and remodeling enzymes.