A [3Fe-4S] cluster and tRNA-dependent aminoacyltransferase BlsK in the biosynthesis of Blasticidin S
A [3Fe-4S] cluster and tRNA-dependent aminoacyltransferase BlsK in the biosynthesis of Blasticidin S
复制标题
杀稻瘟菌素 S 生物合成中的 [3Fe-4S] 簇和 tRNA 依赖性氨酰基转移酶 BlsK
DOI：
10.1073/pnas.2102318118
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发表时间：
2021-07-27
影响因子：
11.1
通讯作者：
Jiang，Ming
中科院分区：
文献类型：
--
作者：
Wang，Xiankun;Zhao，Yuchun;Jiang，Ming
重要性转运RNA（tRNA）将适当活化的氨基酸转移到生长的肽链末端，在初级代谢中发挥重要作用。重要的是，tRNA也被证明在翻译之外发挥作用。在这份报告中，我们提出了一类新的氨酰-tRNA（aa-tRNA）依赖性酶，BlsK，从链霉菌griseochromogenes的特性。BlsK催化杀稻瘟菌素S生物合成中的aa-tRNA依赖性亮氨酰转移反应。BlsK含有一个[3Fe-4S]簇，这是其功能所必需的，在以前鉴定的tRNA依赖性转移酶中是前所未有的。由于BlsK不显示与任何已知功能蛋白的相似性，因此它可能代表一种aa-tRNA依赖性酶。因此，这项工作对tRNA依赖性酶和含铁硫酶都具有广泛的意义。杀稻瘟菌素S是一种肽基核苷抗生素。它的生物合成涉及一个隐蔽的亮氨酰化和两个亮氨酰化的中间体，LDBS和LBS，已发现在以前的研究。亮氨酰化被认为是杀稻瘟菌素S生物合成过程中一种新的自身抗性机制，其中亮氨酰对精氨酸侧链β-氨基的甲基化起重要作用。然而，负责酶和亮氨酰转移过程的相关机制仍有待阐明。在这里，我们报告的结果调查亮氨酰转移步骤形成中间LDBS杀稻瘟菌素生物合成。一个假设的蛋白质，BlsK，其特征在于遗传和体外生化实验。该酶催化亮氨酰从亮氨酰转移RNA（亮氨酰-tRNA）转移到DBS精氨酸侧链上的β-氨基。此外，发现BlsK含有活性所必需的铁硫簇。这些发现提供了一个铁硫蛋白的例子，催化天然产物生物合成途径中的氨酰-tRNA（aa-tRNA）依赖性酰胺键的形成。
Significance Transfer RNA (tRNA) transfer appropriately activated amino acids to the end of the growing peptide chain, playing significant roles in primary metabolism. Importantly, tRNA have also been shown to function outside of translation. In this report, we present the characterization of a new class of aminoacyl-tRNA (aa-tRNA)–dependent enzyme, BlsK, from Streptomyces griseochromogenes. BlsK catalyzes an aa-tRNA–dependent leucyl transfer reaction in blasticidin S biosynthesis. BlsK contains a [3Fe-4S] cluster that is necessary for its function and unprecedented in previously identified tRNA-dependent transferases. Because BlsK does not show similarity to any known functional protein, it may represent a type of aa-tRNA–dependent enzyme. As such, this work has broad implications for both tRNA-dependent and iron–sulfur–containing enzymes. Blasticidin S is a peptidyl nucleoside antibiotic. Its biosynthesis involves a cryptic leucylation and two leucylated intermediates, LDBS and LBS, have been found in previous studies. Leucylation has been proposed to be a new self-resistance mechanism during blasticidin S biosynthesis, and the leucyl group was found to be important for the methylation of β-amino group of the arginine side chain. However, the responsible enzyme and its associated mechanism of the leucyl transfer process remain to be elucidated. Here, we report results investigating the leucyl transfer step forming the intermediate LDBS in blasticidin biosynthesis. A hypothetical protein, BlsK, has been characterized by genetic and in vitro biochemical experiments. This enzyme catalyzes the leucyl transfer from leucyl-transfer RNA (leucyl-tRNA) to the β-amino group on the arginine side chain of DBS. Furthermore, BlsK was found to contain an iron–sulfur cluster that is necessary for activity. These findings provide an example of an iron–sulfur protein that catalyzes an aminoacyl-tRNA (aa-tRNA)–dependent amide bond formation in a natural product biosynthetic pathway.