Biochemical characterization of Hpa2 and Hpa3, two small closely related acetyltransferases from Saccharomyces cerevisiae.
Biochemical characterization of Hpa2 and Hpa3, two small closely related acetyltransferases from Saccharomyces cerevisiae.
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Hpa2 和 Hpa3（来自酿酒酵母的两种小型密切相关的乙酰转移酶）的生化特征。
DOI：
10.1074/jbc.m113.486274
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Sternglanz,Rolf
中科院分区：
文献类型：
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作者：
Sampath,Vinaya;Liu,Bingsheng;Tafrov,Stefan;Srinivasan,Madhusudhan;Rieger,Robert;Chen,EmilyI;Sternglanz,Rolf
基于它们的序列，SaccharomycesparaeHpa 2和Hpa 3蛋白被注释为Gcn 5乙酰转移酶家族的两个密切相关的成员。在这里，我们描述了Hpa 2和Hpa 3 asbona fideacetyltransferases不同的底物特异性的生化特性。突变和MALDI-TOF分析表明，Hpa 3翻译主要从Met-19开始，而不是注释的起始位点Met-1，在Met-27开始有少量产物。当在大肠杆菌中表达并在体外检测时，Hpa 2和Hpa 3（来自Met-19）乙酰化组蛋白和多胺。而Hpa 2乙酰化组蛋白H3和H4（在H3 Lys-14、H4 Lys-5和H4 Lys-12处），Hpa 3仅乙酰化组蛋白H4（在Lys-8处）。此外，Hpa 2，而不是Hpa 3，乙酰化某些小的碱性蛋白质。Hpa 3，而不是Hpa 2，已被报道乙酰化的氨基酸，我们目前的结果与此一致。Hpa 2或Hpa 3的过表达对酵母细胞是有毒的。然而，它们的缺失不显示任何标准的表型缺陷。这些结果表明Hpa 2和Hpa 3是相似但不同的乙酰转移酶，可能与其他已知的乙酰转移酶在体内乙酰化组蛋白和其他小蛋白中具有重叠的作用。虽然Hpa 2和Hpa 3在序列上非常相似，但它们对底物的偏好略有不同。
Based on their sequences, theSaccharomyces cerevisiaeHpa2 and Hpa3 proteins are annotated as two closely related members of the Gcn5 acetyltransferase family. Here, we describe the biochemical characterization of Hpa2 and Hpa3 asbona fideacetyltransferases with different substrate specificities. Mutational and MALDI-TOF analyses showed that Hpa3 translation initiates primarily from Met-19 rather than the annotated start site, Met-1, with a minor product starting at Met-27. When expressed inEscherichia coliand assayedin vitro, Hpa2 and Hpa3 (from Met-19) acetylated histones and polyamines. Whereas Hpa2 acetylated histones H3 and H4 (at H3 Lys-14, H4 Lys-5, and H4 Lys-12), Hpa3 acetylated only histone H4 (at Lys-8). Additionally, Hpa2, but not Hpa3, acetylated certain small basic proteins. Hpa3, but not Hpa2, has been reported to acetylated-amino acids, and we present results consistent with that. Overexpression of Hpa2 or Hpa3 is toxic to yeast cells. However, their deletions do not show any standard phenotypic defects. These results suggest that Hpa2 and Hpa3 are similar but distinct acetyltransferases that might have overlapping roles with other known acetyltransferasesin vivoin acetylating histones and other small proteins.Background: Based on their sequences, the closely related yeast Hpa2 and Hpa3 proteins appear to be acetyltransferases.Results: Hpa2 and Hpa3 acetylate histones, polyamines, and some small basic proteins.Conclusion: Although Hpa2 and Hpa3 are very similar in sequence, they have somewhat different substrate preferences.Significance: This is the first biochemical characterization of these two acetyltransferases.