Insights into the post-translational modifications of archaeal Sis10b (Alba): lysine-16 is methylated, not acetylated, and this does not regulate transcription or growth
Insights into the post-translational modifications of archaeal Sis10b (Alba): lysine-16 is methylated, not acetylated, and this does not regulate transcription or growth
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深入了解古细菌 Sis10b (Alba) 的翻译后修饰：赖氨酸 16 被甲基化，而非乙酰化，这不会调节转录或生长
DOI：
10.1111/mmi.13973
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发表时间：
2018-07-01
影响因子：
3.6
通讯作者：
Huang, Li
中科院分区：
文献类型：
--
作者：
Cao, Jingjing;Wang, Qian;Huang, Li
Sac10b家族的核酸结合蛋白，也被称为Alba（乙酰化降低结合亲和力），在古细菌中高度保守。报道了一种来自solfataricus Sulfolobus Sac10b的同源物Sso10b在K16的-氨基和n端残基的-氨基上被乙酰化。值得注意的是，K16的乙酰化降低了Sso10b对DNA的亲和力，并在体外抑制转录。在这里，我们发现来自Sulfolobus islandicus的Sac10b同源物Sis10b经历了一系列翻译后修饰（PTMs）。Sso10b和Sso10b中的K16均未发生乙酰化。用K16代替R16会导致该位点的ptm缺失，但对细胞的生长影响不大，只会导致一小部分基因的表达发生轻微变化。Sis10b的n端几乎完全乙酰化。末端乙酰化的减少或缺失导致Sis10b的细胞浓度显著增加，表明该修饰参与了对蛋白质周转的控制。这些结果澄清了Sac10b同源物的PTMs，并阐明了该蛋白乙酰化的作用。
Nucleic acid-binding proteins of the Sac10b family, also referred to as Alba (for acetylation lowers binding affinity), are highly conserved in Archaea. It was reported that Sso10b, a Sac10b homologue from Sulfolobus solfataricus, was acetylated at the -amino group of K16 and the -amino group of the N-terminal residue. Notably, acetylation of K16 reduced the affinity of Sso10b for DNA and de-repressed transcription in vitro. Here, we show that Sis10b, a Sac10b homologue from Sulfolobus islandicus, underwent a range of post-translational modifications (PTMs). K16 in Sis10b as well as Sso10b was not acetylated. Substitution of K16 for R16, which resulted in the loss of the PTMs at the site, showed little effect on the growth of the cell and resulted in only a slight change in the expression of a very small fraction of the genes. The N-terminus of Sis10b was nearly completely N-acetylated. The reduction or loss of the terminal acetylation led to a significant increase in the cellular concentration of Sis10b, suggesting the involvement of the modification in the control of the turnover of the protein. These results have clarified the PTMs of Sac10b homologues and shed light on the proposed roles of acetylation of the protein.