Abstract：
Triceptides are cyclophane-containing ribosomally synthesized and post-translationally modified peptides. The characteristic cross-links are formed between an aromatic ring to Cβ on three-residue Ω1X2X3 motifs (Ω1 = aromatic). Here, we explored the promiscuity of the XYE family triceptide maturase, XncB from Xenorhabdus nematophila DSM 3370. Single amino acid variants were coexpressed with XncB in vivo in Escherichia coli, and we show that a variety of amino acids can be incorporated into the Phe-Gly-Asn cyclophane. Aromatic amino acids at the X3 position were accepted by the enzyme but yielded hydroxylated, rather than the typical cyclophane, products. These studies show that oxygen can be inserted but diverges in the final product formed relative to daropeptide maturases. Finally, truncations of the leader peptide showed that it is necessary for complete modification by XncB.
摘要：
三肽是含环法的核糖体合成和翻译后修饰的肽。特征性交联在三个残基Ω1X2X3基序（Ω1=芳族）上的芳族环与Cβ之间形成。这里,我们探索了XYE家族三肽成熟酶的滥交，XncB来自嗜线虫DSM3370。单氨基酸变体与XncB在大肠杆菌体内共表达，我们表明，可以将多种氨基酸掺入Phe-Gly-Asn环法中。X3位的芳香族氨基酸被酶接受，但产生羟基化，而不是典型的环法，产品。这些研究表明，相对于达罗肽成熟酶，氧气可以插入但在形成的最终产物中发散。最后,前导肽的截短表明，必须通过XncB进行完全修饰。
