Dehydrophos is a tripeptide phosphonate antibiotic produced by Streptomyces luridus. Its biosynthetic pathway involves the use of aminoacyl-tRNA (aa-tRNA) for amide bond formation. The first amide bond during biosynthesis is formed by DhpH-C, a peptidyltransferase that utilizes Leu-tRNA^Leu. DhpH-C is a member of a burgeoning family of natural product biosynthetic enzymes that make use of aa-tRNA outside of canonical translation activities in the cell. Here, we used site-directed mutagenesis of both DhpH-C and tRNA^Leu to investigate the enzyme mechanism and substrate specificity, respectively, and analyzed the substrate scope for the production of a set of dipeptides. DhpH-C appears to recognize both the amino acyl group on the tRNA and the tRNA acceptor stem, and the enzyme can accept other hydrophobic residues, in addition to leucine. These results contribute to a better understanding of enzyme-aa-tRNA interactions and the growing exploration of aa-tRNA usage beyond translation.

中文翻译：

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脱磷生物合成过程中酰胺键形成的研究

Dehydrophos是luridus链霉菌（Streptomyces luridus）生产的一种三肽膦酸酯抗生素。它的生物合成途径涉及使用氨酰基-tRNA（aa-tRNA）形成酰胺键。生物合成过程中的第一个酰胺键由DhpH-C（一种利用Leu-tRNA ^Leu的肽基转移酶）形成。DhpH-C是新兴的天然产物生物合成酶家族的成员，该酶在细胞中的规范翻译活性之外利用aa-tRNA。在这里，我们使用了DhpH-C和tRNA ^Leu的定点诱变分别研究酶的机制和底物特异性，并分析了生产一套二肽的底物范围。DhpH-C似乎可以识别tRNA和tRNA受体茎上的氨基酰基，并且该酶除亮氨酸外还可以接受其他疏水残基。这些结果有助于更好地理解酶-aa-tRNA的相互作用，以及对翻译以外的aa-tRNA用途的不断探索。