Liu Fangfang, van Heel Auke J, Kuipers Oscar P
Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.
Omnicin Therapeutics, Groningen, Netherlands.
Front Microbiol. 2024 Feb 15;15:1337647. doi: 10.3389/fmicb.2024.1337647. eCollection 2024.
Circular bacteriocins form a distinct group of antimicrobial peptides (AMPs) characterized by their unique head-to-tail ligated circular structure and functional properties. They belong to the ribosomally synthesized and post-translationally modified peptide (RiPP) family. The ribosomal origin of these peptides facilitates rapid diversification through mutations in the precursor genes combined with specific modification enzymes. In this study, we primarily explored the bacteriocin engineering potential of circularin A, a circular bacteriocin produced by ATCC 25752. Specifically, we employed strategies involving α-helix replacements and disulfide bond introductions to investigate their effects on both biosynthesis and bioactivity of the bacteriocin. The results show the feasibility of peptide engineering to introduce certain structural properties into circularin A through carefully designed approaches. The introduction of cysteines for potential disulfide bonds resulted in a substantial reduction in bacteriocin biosynthesis and/or bioactivity, indicating the importance of maintaining dynamic flexibility of α-helices in circularin A, while reduction of the potential disulfide in one case increased the activity. The 5 α-helices of circularin A were respectively replaced by corresponding helices from another circular peptide, enterocin AS-48, and modestly active peptides were obtained in a few cases. Overall, this study provides valuable insights into the engineering potential of circular bacteriocins as antimicrobial agents, including their structural and functional restrictions and their suitability as peptide engineering scaffolds. This helps to pave the way for the development of novel antimicrobial peptides with tailored properties based on circular bacteriocins.
环状细菌素构成了一类独特的抗菌肽（AMPs），其特征在于具有独特的头对尾连接的环状结构和功能特性。它们属于核糖体合成及翻译后修饰肽（RiPP）家族。这些肽的核糖体起源有助于通过前体基因中的突变与特定修饰酶相结合实现快速多样化。在本研究中，我们主要探索了由ATCC 25752产生的环状细菌素A的细菌素工程潜力。具体而言，我们采用了涉及α-螺旋替换和二硫键引入的策略，以研究它们对细菌素生物合成和生物活性的影响。结果表明，通过精心设计的方法对肽进行工程改造，将某些结构特性引入环状细菌素A是可行的。引入用于潜在二硫键的半胱氨酸导致细菌素生物合成和/或生物活性大幅降低，这表明保持环状细菌素A中α-螺旋的动态灵活性很重要，而在一种情况下减少潜在二硫键则提高了活性。环状细菌素A的5个α-螺旋分别被另一种环状肽肠球菌素AS-48的相应螺旋所取代，在少数情况下获得了活性适中的肽。总体而言，本研究为环状细菌素作为抗菌剂的工程潜力提供了有价值的见解，包括它们的结构和功能限制以及作为肽工程支架的适用性。这有助于为基于环状细菌素开发具有定制特性的新型抗菌肽铺平道路。
