Seefeldt A Carolin, Graf Michael, Pérébaskine Natacha, Nguyen Fabian, Arenz Stefan, Mardirossian Mario, Scocchi Marco, Wilson Daniel N, Innis C Axel
Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac 33607, France U1212, Inserm, Bordeaux 33076, France UMR 5320, CNRS, Bordeaux 33076, France.
Gene Center and Department for Biochemistry, University of Munich, Munich 81377, Germany.
Nucleic Acids Res. 2016 Mar 18;44(5):2429-38. doi: 10.1093/nar/gkv1545. Epub 2016 Jan 20.
Proline-rich antimicrobial peptides (PrAMPs) produced as part of the innate immune response of animals, insects and plants represent a vast, untapped resource for the treatment of multidrug-resistant bacterial infections. PrAMPs such as oncocin or bactenecin-7 (Bac7) interact with the bacterial ribosome to inhibit translation, but their supposed specificity as inhibitors of bacterial rather than mammalian protein synthesis remains unclear, despite being key to developing drugs with low toxicity. Here, we present crystal structures of the Thermus thermophilus 70S ribosome in complex with the first 16 residues of mammalian Bac7, as well as the insect-derived PrAMPs metalnikowin I and pyrrhocoricin. The structures reveal that the mammalian Bac7 interacts with a similar region of the ribosome as insect-derived PrAMPs. Consistently, Bac7 and the oncocin derivative Onc112 compete effectively with antibiotics, such as erythromycin, which target the ribosomal exit tunnel. Moreover, we demonstrate that Bac7 allows initiation complex formation but prevents entry into the elongation phase of translation, and show that it inhibits translation on both mammalian and bacterial ribosomes, explaining why this peptide needs to be stored as an inactive pro-peptide. These findings highlight the need to consider the specificity of PrAMP derivatives for the bacterial ribosome in future drug development efforts.
富含脯氨酸的抗菌肽(PrAMPs)作为动物、昆虫和植物先天免疫反应的一部分产生,是治疗多重耐药细菌感染的巨大未开发资源。诸如癌菌素或杆菌肽-7(Bac7)等PrAMPs与细菌核糖体相互作用以抑制翻译,但其作为细菌而非哺乳动物蛋白质合成抑制剂的所谓特异性仍不清楚,尽管这是开发低毒药物的关键。在此,我们展示了嗜热栖热菌70S核糖体与哺乳动物Bac7的前16个残基以及昆虫来源的PrAMPs金属尼可温I和红蝽菌素形成复合物的晶体结构。这些结构表明,哺乳动物Bac7与核糖体的相互作用区域与昆虫来源的PrAMPs相似。一致地,Bac7和癌菌素衍生物Onc112能有效地与靶向核糖体出口通道的抗生素(如红霉素)竞争。此外,我们证明Bac7允许起始复合物形成,但阻止进入翻译延伸阶段,并表明它在哺乳动物和细菌核糖体上均抑制翻译,这解释了为什么这种肽需要作为无活性的前体肽储存。这些发现突出了在未来药物开发工作中考虑PrAMP衍生物对细菌核糖体特异性的必要性。