Application of modified histone peptide arrays in chromatin research

Various post-translational modifications (PTMs) have been identified on histone proteins, which occur at hundreds of different sites. Histone PTMs influence the chromatin structure and serve as binding sites for reading domains, which further mediate downstream effects. Histone PTM antibodies or recombinant proteins derived from reading domains are unique research reagents essentially required to study histone modifications. To validate their specificity, histone PTM peptide arrays are used, because they allow to investigate the binding of proteins to a large number of different peptides in one experiment. Furthermore, histone PTM peptide arrays can be used to characterize reading domains and study the specificity of histone modifying enzymes. Here, we provide an overview of histone PTM peptide arrays, highlight some of their applications and compare different commercial histone PTM peptide arrays, viz. MODified Histone Peptide Array, AbSurance Pro Histone Peptide Microarrays, EpiTriton Histone Peptide Array and Histone Code Microarrays. These arrays contain histone peptides with several post-translational modifications in many different combinations, but they differ in peptide synthesis and immobilization methods, peptide and PTM coverage, and PTM combinatorial potential. In addition, some special applications of histone PTM peptide arrays like custom arrays or double peptide arrays are described.