Substrate Scope for Human Histone Lysine Acetyltransferase KAT8

Abstract

Biomedically important histone lysine acetyltransferase KAT8 catalyses the acetyl coenzyme A-dependent acetylation of lysine on histone and other proteins. Here, we explore the ability of human KAT8 to catalyse the acetylation of histone H4 peptides possessing lysine and its analogues at position 16 (H4K16). Our synthetic and enzymatic studies on chemically and structurally diverse lysine mimics demonstrate that KAT8 also has a capacity to acetylate selected lysine analogues that possess subtle changes on the side chain and main chain. Overall, this work highlights that KAT8 has a broader substrate scope beyond natural lysine, and contributes to the design of new chemical probes targeting KAT8 and other members of the histone lysine acetyltransferase (KAT) family.

Investigation of in vitro histone H3 glycosylation using H3 tail peptides

“…Furthermore, the expected product 15 of OGT-catalyzed glycosylation of 2 was chemically prepared as a reference standard, and to investigate the ability of OGA to catalyze deglycosylation of 15. Finally, chemically modified peptides bearing a Ser10GlcNAc in combination with methylation or acetylation marks of neighboring Lys9 (16)(17) or asymmetric dimethylated Arg8 (18) were also investigated as OGA substrates.…”

“…As histone tails are flexible and contain a relatively modest recognition domain, showing activity for the enzymes that introduce PTMs (known as 'writers') or remove PTMs (known as 'erasers') on small peptide fragments, the core protein is of little influence in most cases and can be omitted in enzymatic assays. For example, we have shown that histone lysine methylation and acetylation can be studied on small histone tail peptides in vitro, exploring the tolerance of unnatural lysine analogs by the catalytic domains of lysine methyltransferases (KMTs) and acetyltransferases (KATs) [12][13][14][15][16][17][18] . Furthermore microarrays of histone tail peptide fragments are commonly used to discover interactions and interrogate with a host of histone readers 19,20 .…”

Probing lysine posttranslational modifications by unnatural amino acids

“…In the studies of KATs, a variety of analogues have been used to assess their substrate scope. 71,74,[106][107][108] Human KATs appeared to be relatively promiscuous when it comes to the chain length of the lysine substrate; whereas shorter lysine analogues were not acetylated, extension of the side chain by three carbons was still tolerated in some cases, while a two-carbon extension was universally accepted (Fig. 7C, Chain length).…”

“…106 KAT8, a biomedically relevant KAT that catalyses the acetylation of histone H4 and transcription factor p53, was investigated with regards to its substrate scope. 107 Several chemical features of the lysine substrate were modified, including side chain, nucleophilicity, backbone and stereochemistry (Fig. 7C).…”

“…7C). 107 The synthetically easily accessible lysine mimic γ-thialysine (K c ) was also investigated as a substrate for human KATs. 108 Interestingly, γ-thialysine behaved as an excellent analogue for acetylation, also accepting the slightly larger propionyl group, further establishing γ-thialysine as a suitable mimic for studies of PTMs of lysine with a potential application in full-length proteins.…”