A sensitive protein-based sensor for quantifying histone acetylation levels

• A sensitive probe was developed to detect lysine acetylation in histone H3.
• The probe can quantitatively detect acetylation levels between 5% and 100%.
• The probe can detect small amounts of acetylated histone proteins at ~30 ng.

H3K14ac (acetylation of lysine 14 of histone H3) is one of the most important epigenetic modifications in cells. Aberrant changes in H3K14ac are commonly found in various types of cancers and neurological disorders. Current detection approaches for histone modifications, however, require either tedious sample pre-treatments or lack the quantitative accuracy required for biochemical and biomedical applications. In this study, we engineered a protein sensor using the amino acid sequences derived from the bromodomain of human polybromo-1 (PB1). The protein sensor was conjugated to a fluorescent dye for sensitive detection of H3K14ac. Different detection conditions, such as additive concentrations and probe concentrations, were optimally selected by balancing signal strength (IRel) and signal-to-noise ratio (SNR). The protein sensor was verified using histone H3 peptides containing different H3K14 acetylation levels. The detection signal was found to be linearly dependent on acetylation levels of H3K14 ranging from 5% to 100%. The designed platform can be used for screening epigienetic drugs regulating H3K14 acetylation levels as well as monitoring H3K14 acetylation level of circulating nucleosomes for disease progression.

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