The Creatininase Homolog MftE from Mycobacterium smegmatis Catalyzes a Peptide Cleavage Reaction in the Biosynthesis of a Novel Ribosomally Synthesized Post-translationally Modified Peptide (RiPP)
The Creatininase Homolog MftE from Mycobacterium smegmatis Catalyzes a Peptide Cleavage Reaction in the Biosynthesis of a Novel Ribosomally Synthesized Post-translationally Modified Peptide (RiPP)
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DOI：
10.1074/jbc.m116.762062
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发表时间：
2017-03-01
影响因子：
4.8
通讯作者：
Bandarian, Vahe
中科院分区：
文献类型：
--
作者：
Bruender, Nathan A.;Bandarian, Vahe
大多数核糖体合成的和后修饰的肽（RiPP）天然产物通过定制酶加工以产生仍然可识别为基于肽的复杂天然产物。然而，一些剪裁酶在合成小分子的途中分解肽。一种结构尚不清楚的小分子天然产物--分枝杆菌素，被认为是通过许多分枝杆菌菌株中发现的mft基因簇以这种方式合成的。这个簇包含至少六个基因，这些基因似乎在物种间是保守的。我们以前已经表明，一种酶从这个集群，MftC，催化的底物肽MftA的C-末端Tyr的氧化脱羧反应，需要MftB蛋白。在此，我们表明，mftE编码的肌酸酶同源物，催化氧化脱羧MftA肽裂解，以释放其最后两个残基，包括C-末端脱羧酪氨酸（VY*）。与需要MftB发挥功能的MftC不同，MftE在不存在MftB的情况下催化裂解反应。这种新型代谢物VY* 的鉴定支持了mft簇参与从MftA肽生成小分子的观点。通过体外重建MftB、MftC和MftE的活性从MftA产生VY* 的能力为鉴定由mft簇编码的蛋白质产生的新型代谢物奠定了基础。
Most ribosomally synthesized and post-translationally modified peptide (RiPP) natural products are processed by tailoring enzymes to create complex natural products that are still recognizably peptide-based. However, some tailoring enzymes dismantle the peptide en route to synthesis of small molecules. A small molecule natural product of as yet unknown structure, mycofactocin, is thought to be synthesized in this way via the mft gene cluster found in many strains of mycobacteria. This cluster harbors at least six genes, which appear to be conserved across species. We have previously shown that one enzyme from this cluster, MftC, catalyzes the oxidative decarboxylation of the C-terminal Tyr of the substrate peptide MftA in a reaction that requires the MftB protein. Herein we show that mftE encodes a creatininase homolog that catalyzes cleavage of the oxidatively decarboxylated MftA peptide to liberate its final two residues, including the C-terminal decarboxylated Tyr (VY*). Unlike MftC, which requires MftB for function, MftE catalyzes the cleavage reaction in the absence of MftB. The identification of this novel metabolite, VY*, supports the notion that the mft cluster is involved in generating a small molecule from the MftA peptide. The ability to produce VY* from MftA by in vitro reconstitution of the activities of MftB, MftC, and MftE sets the stage for identification of the novel metabolite that results from the proteins encoded by the mft cluster.