Steric complementarity directs sequence promiscuous leader binding in RiPP biosynthesis
Steric complementarity directs sequence promiscuous leader binding in RiPP biosynthesis
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DOI：
10.1073/pnas.1908364116
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发表时间：
2019-11-26
影响因子：
11.1
通讯作者：
Nair, Satish K.
中科院分区：
文献类型：
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作者：
Chekan, Jonathan R.;Ongpipattanakul, Chayanid;Nair, Satish K.
产生核糖体合成和翻译后修饰多肽(RIPP)天然产物的酶已经引起了人们的极大兴趣，因为它们能够产生大量化学上不同的支架文库。据预测，这种RIPP生物合成酶通过对前导序列的序列特异性识别与其相应的肽底物结合，在核心序列上安装翻译后修饰后将其移除。在一个给定的RIPP类内的前导序列的保守性，在其他不同的前体多肽中，进一步支持了严格的序列特异性对于前导肽结合是必要的这一概念。在这里，我们证明了由套索多肽类Ripps中的生物合成酶结合的先导是由最少数量的疏水相互作用指导的。生化和结构数据说明了单个前导结合结构域如何利用促进疏水堆积的保守基序与序列不同的前导肽结合。这个简单的基序存在于非同源多肽中，通过结合来自几个不同套索生物合成系统的结构域，导致低微摩尔亲和力结合。我们还证明，这些观察结果可能延伸到其他RIPP生物合成类。结合基序的可移植性为半合成杂交RIPP产品的工程开辟了道路。
Enzymes that generate ribosomally synthesized and posttranslationally modified peptide (RiPP) natural products have garnered significant interest, given their ability to produce large libraries of chemically diverse scaffolds. Such RiPP biosynthetic enzymes are predicted to bind their corresponding peptide substrates through sequence-specific recognition of the leader sequence, which is removed after the installation of posttranslational modifications on the core sequence. The conservation of the leader sequence within a given RiPP class, in otherwise disparate precursor peptides, further supports the notion that strict sequence specificity is necessary for leader peptide engagement. Here, we demonstrate that leader binding by a biosynthetic enzyme in the lasso peptide class of RiPPs is directed by a minimal number of hydrophobic interactions. Biochemical and structural data illustrate how a single leader-binding domain can engage sequence-divergent leader peptides using a conserved motif that facilitates hydrophobic packing. The presence of this simple motif in noncognate peptides results in low micromolar affinity binding by binding domains from several different lasso biosynthetic systems. We also demonstrate that these observations likely extend to other RiPP biosynthetic classes. The portability of the binding motif opens avenues for the engineering of semisynthetic hybrid RiPP products.