Lv Xinchen, Zhang Yuanyuan, Sun Ke, Yang Qi, Luo Jianhua, Tao Liang, Lu Peilong
Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310024, China.
Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, 310024, China.
Nat Commun. 2024 Oct 2;15(1):8521. doi: 10.1038/s41467-024-52582-1.
Clostridioides difficile toxin B (TcdB) is the key virulence factor accounting for C. difficile infection-associated symptoms. Effectively neutralizing different TcdB variants with a universal solution poses a significant challenge. Here we present the de novo design and characterization of pan-specific mini-protein binders against major TcdB subtypes. Our design successfully binds to the first receptor binding interface (RBI-1) of the varied TcdB subtypes, exhibiting affinities ranging from 20 pM to 10 nM. The cryo-electron microscopy (cryo-EM) structures of the mini protein binder in complex with TcdB1 and TcdB4 are consistent with the computational design models. The engineered and evolved variants of the mini-protein binder and chondroitin sulfate proteoglycan 4 (CSPG4), another natural receptor that binds to the second RBI (RBI-2) of TcdB, better neutralize major TcdB variants both in cells and in vivo, as demonstrated by the colon-loop assay using female mice. Our findings provide valuable starting points for the development of therapeutics targeting C. difficile infections (CDI).
艰难梭菌毒素B（TcdB）是导致艰难梭菌感染相关症状的关键毒力因子。用一种通用的方法有效中和不同的TcdB变体是一项重大挑战。在此，我们展示了针对主要TcdB亚型的泛特异性微型蛋白结合剂的从头设计和表征。我们的设计成功结合了不同TcdB亚型的第一个受体结合界面（RBI-1），亲和力范围为20 pM至10 nM。微型蛋白结合剂与TcdB1和TcdB4复合物的冷冻电子显微镜（cryo-EM）结构与计算设计模型一致。微型蛋白结合剂的工程化和进化变体以及硫酸软骨素蛋白聚糖4（CSPG4），另一种与TcdB的第二个RBI（RBI-2）结合的天然受体，在细胞和体内能更好地中和主要的TcdB变体，这在使用雌性小鼠的结肠环试验中得到了证明。我们的研究结果为开发针对艰难梭菌感染（CDI）的治疗方法提供了有价值的起点。
