原核生物BirA连接酶可将生物素连接到组蛋白H3的K4、K9、K18和K23位点上。
Prokaryotic BirA ligase biotinylates K4, K9, K18 and K23 in histone H3.
作者信息
Kobza Keyna, Sarath Gautam, Zempleni Janos
机构信息
Departments of Nutrition and Health Sciences, University of Nebraska at Lincoln, Lincoln, NE, USA.
出版信息
BMB Rep. 2008 Apr 30;41(4):310-5. doi: 10.5483/bmbrep.2008.41.4.310.
BirA ligase is a prokaryotic ortholog of holocarboxylase synthetase (HCS) that can biotinylate proteins. This study tested the hypothesis that BirA ligase catalyzes the biotinylation of eukaryotic histones. If so, this would mean that recombinant BirA ligase is a useful surrogate for HCS in studies of histone biotinylation. The biological activity of recombinant BirA ligase was confirmed by enzymatic biotinylation of p67. In particular, it was found that BirA ligase biotinylated both calf thymus histone H1 and human bulk histone extracts. Incubation of recombinant BirA ligase with H3-based synthetic peptides showed that lysines 4, 9, 18, and 23 in histone H3 are the targets for the biotinylation by BirA ligase. Modification of the peptides (e.g., serine phosphorylation) affected the subsequent biotinylation by BirA ligase, suggesting crosstalk between modifications. In conclusion, this study suggests that prokaryotic BirA ligase is a promiscuous enzyme and biotinylates eukaryotic histones. Moreover the biotinylation of histones by BirA ligase is consistent with the proposed role of human HCS in chromatin.
BirA连接酶是全羧化酶合成酶（HCS）的原核直系同源物，能够对蛋白质进行生物素化修饰。本研究检验了BirA连接酶催化真核生物组蛋白生物素化修饰的假说。如果真是这样，这将意味着在组蛋白生物素化修饰研究中，重组BirA连接酶是HCS的一种有用替代物。通过对p67进行酶促生物素化修饰，证实了重组BirA连接酶的生物活性。具体而言，发现BirA连接酶可对小牛胸腺组蛋白H1和人总组蛋白提取物进行生物素化修饰。重组BirA连接酶与基于H3的合成肽一起孵育表明，组蛋白H3中的赖氨酸4、9、18和23是BirA连接酶进行生物素化修饰的靶点。对肽进行修饰（例如丝氨酸磷酸化）会影响随后BirA连接酶的生物素化修饰，这表明修饰之间存在相互作用。总之，本研究表明原核生物BirA连接酶是一种通用性酶，可对真核生物组蛋白进行生物素化修饰。此外，BirA连接酶对组蛋白的生物素化修饰与人类HCS在染色质中所起的作用一致。
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