Moreira Ryan, Chakraborty Bidisha, Yang Yi, Padhi Chandrashekhar, Gilmore Michael S, Nair Satish K, van der Donk Wilfred A
Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Nat Commun. 2025 Jul 28;16(1):6936. doi: 10.1038/s41467-025-62161-7.
The enterococcal cytolysin is a toxic, two-component ribosomally synthesized and post-translationally modified peptide (RiPP) produced by pathogenic Enterococcus faecalis. Cytolysin-producing (C+) E. faecalis resides in the gut microbiome in a commensal role, but results in negative clinical outcomes in alcoholic hepatitis patients. To potentially combat cytolysin virulence, we report inhibitors of its maturation. An extracellular serine protease CylA that is essential for toxin activation is chosen as target. A series of α-aminopeptide boronic acids are designed and synthesized that block cytolysin maturation at low micromolar to nanomolar concentrations in vitro. A crystal structure of CylA provides insights into substrate recognition, autocatalytic activation of the enzyme, and toxin maturation. The inhibitors block hemolytic activity, reduce the amount of cytolysin, and attenuate expression of the cytolysin biosynthetic gene cluster without impeding cell growth. These studies provide a potential route to the development of treatments for cytolysin-induced disease states.
肠球菌溶血素是一种由致病性粪肠球菌产生的有毒的、由核糖体合成并经翻译后修饰的双组分肽（RiPP）。产生溶血素的（C+）粪肠球菌在肠道微生物群中以共生菌的形式存在，但在酒精性肝炎患者中会导致负面的临床结果。为了潜在地对抗溶血素的毒性，我们报告了其成熟过程的抑制剂。一种对毒素激活至关重要的细胞外丝氨酸蛋白酶CylA被选为靶点。设计并合成了一系列α-氨基肽硼酸，它们在体外以低微摩尔到纳摩尔的浓度阻断溶血素的成熟。CylA的晶体结构为底物识别、酶的自催化激活和毒素成熟提供了见解。这些抑制剂可阻断溶血活性，减少溶血素的量，并减弱溶血素生物合成基因簇的表达，同时不影响细胞生长。这些研究为开发针对溶血素诱导疾病状态的治疗方法提供了一条潜在途径。
