CBP (bromodomain) + H3K56ac

3D Model

Histones are often modifying post-transcriptionally in order to control and regulate processes such as DNA transcription, DNA replication and more. One of the most common histone modifications is lysine acetylation. Of histone H3, acetylated lysine 56 (H3K56ac) neutralises the positive charge induced by the K56 sidechain in order to break the hydrogen bonds with the DNA backbone which increases the accessibility of the DNA due to the unwrapping. Mammalian cell H3K56 is acetylated by the CREB binding protein (CBP). The CBP bromodomain particularly has a high affinity for H3K56 over other histones. This recognition results in histone acetyltransferase (HAT) of H3K56 which enhances histone chaperones and their affinity to bind to H3-H4 dimers. However, the mechanism which the bromodomain of CBP used to recognise H3K52ac has still not been confirmed and validated. However, structural analyses have revealed the importance of certain factors.