Prokaryotic BirA ligase biotinylates K4 K9 K18 and K23 in histone H3

摘要

BirA ligase, a prokaryotic ortholog of holocarboxylase synthetase (HCS), is known to biotinylate proteins. Here, we tested the hypothesis that BirA ligase catalyzes biotinylation of eukaryotic histones. If so, this would render recombinant BirA ligase a useful surrogate for HCS in studies of histone biotinylation. Biological activity of recombinant BirA ligase was confirmed by enzymatic biotinylation of p67. Importantly, BirA ligase biotinylated both calf thymus histone H1 and human bulk histone extracts. Incubation of recombinant BirA ligase with H3-based synthetic peptides revealed that lysines 4, 9, 18, and 23 in histone H3 are targets for biotinylation by BirA ligase. Modifications of peptides (e.g., serine phosphorylation) affected subsequent biotinylation by BirA ligase, suggesting crosstalk among modifications. In conclusion, this study suggests that prokaryotic BirA ligase is a promiscuous enzyme and biotinylates eukaryotic histones; biotinylation of histones by BirA ligase is consistent with the proposed role of human HCS in chromatin.