Johnstone Bronte A, Christie Michelle P, Joseph Riya, Morton Craig J, Brown Hamish G, Hanssen Eric, Sanford Tristan C, Abrahamsen Hunter L, Tweten Rodney K, Parker Michael W
Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia.
ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia.
Sci Adv. 2025 Mar 28;11(13):eadt2127. doi: 10.1126/sciadv.adt2127.
Pore-forming proteins comprise a highly diverse group of proteins exemplified by the membrane attack complex/perforin (MACPF), cholesterol-dependent cytolysin (CDC), and gasdermin superfamilies, which all form gigantic pores (>150 angstroms). A recently found family of pore-forming toxins, called CDC-like proteins (CDCLs), are wide-spread in gut microbes and are a prevalent means of antibacterial antagonism. However, the structural aspects of how CDCLs assemble a pore remain a mystery. Here, we report the crystal structure of a proteolytically activated CDCL and cryo-electron microscopy structures of a prepore-like intermediate and a transmembrane pore providing detailed snapshots across the entire pore-forming pathway. These studies reveal a sophisticated array of regulatory features to ensure productive pore formation, and, thus, CDCLs straddle the MACPF, CDC, and gasdermin lineages of the giant pore superfamilies.
成孔蛋白构成了一类高度多样化的蛋白质，以膜攻击复合物/穿孔素（MACPF）、胆固醇依赖性细胞溶素（CDC）和gasdermin超家族为代表，它们都能形成巨大的孔（>150埃）。最近发现的一类成孔毒素，称为CDC样蛋白（CDCL），广泛存在于肠道微生物中，是一种普遍的抗菌拮抗手段。然而，CDCL如何组装成孔的结构方面仍是个谜。在这里，我们报告了一种经蛋白水解激活的CDCL的晶体结构，以及一种类似前孔中间体和跨膜孔的冷冻电子显微镜结构，提供了整个成孔途径的详细快照。这些研究揭示了一系列复杂的调节特征，以确保有效的孔形成，因此，CDCL跨越了巨型孔超家族的MACPF、CDC和gasdermin谱系。
