Human Naa50p (Nat5/San) Displays Both Protein Nα- and Nε-Acetyltransferase Activity
Human Naa50p (Nat5/San) Displays Both Protein Nα- and Nε-Acetyltransferase Activity
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DOI：
10.1074/jbc.m109.001347
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发表时间：
2009-11-06
影响因子：
4.8
通讯作者：
Lillehaug, Johan R.
中科院分区：
文献类型：
--
作者：
Evjenth, Rune;Hole, Kristine;Lillehaug, Johan R.
蛋白质乙酰化是由位点选择性乙酰转移酶介导的广泛修饰。KAT（赖氨酸N-乙酰基转移酶）修饰组蛋白和其他蛋白质上的特定赖氨酸的侧链，是调节基因表达的中心过程。N-α-末端乙酰化发生在核糖体上，其中新生多肽的α氨基被NAT（N-末端乙酰转移酶）乙酰化。在酵母中，三种不同的NAT复合物被鉴定为NatA、NatB和NatC。NatA由两个主要亚基组成，催化亚基Naa10p（Ard1p）和Naa15p（Nat1p）。Naa50p（Nat5）与NatA在物理上结合。在人类中，hNaa50 p被证明具有乙酰转移酶活性，并对染色体分离很重要。在这项研究中，我们使用纯化的重组hNaa50 p和多种寡肽底物，以确定和表征的N-α-乙酰转移酶活性的hNaa50 p。作为优选的底物，该活性使具有N末端Met-Leu-Xxx-Pro的寡肽乙酰化。此外，hNaa50 p在体外自乙酰化赖氨酸34、37和140，调节hNaa50 p底物特异性。此外，在体外检测到组蛋白4作为hNaa50p KAT底物。因此，我们的研究结果提供了第一个具有KAT和NAT活性的酶的实验证据。
Protein acetylation is a widespread modification that is mediated by site-selective acetyltransferases. KATs (lysine N-epsilon-acetyltransferases), modify the side chain of specific lysines on histones and other proteins, a central process in regulating gene expression. N-alpha-terminal acetylation occurs on the ribosome where the alpha amino group of nascent polypeptides is acetylated by NATs(N-terminal acetyltransferase). In yeast, three different NAT complexes were identified NatA, NatB, and NatC. NatA is composed of two main subunits, the catalytic subunit Naa10p (Ard1p) and Naa15p (Nat1p). Naa50p (Nat5) is physically associated with NatA. In man, hNaa50p was shown to have acetyltransferase activity and to be important for chromosome segregation. In this study, we used purified recombinant hNaa50p and multiple oligopeptide substrates to identify and characterize an N-alpha-acetyltransferase activity of hNaa50p. As the preferred substrate this activity acetylates oligopeptides with N termini Met-Leu-Xxx-Pro. Furthermore, hNaa50p autoacetylates lysines 34, 37, and 140 in vitro, modulating hNaa50p substrate specificity. In addition, histone 4 was detected as a hNaa50p KAT substrate in vitro. Our findings thus provide the first experimental evidence of an enzyme having both KAT and NAT activities.