College of Food Science and Technology, Shanghai Ocean University, Shanghai, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
J Fish Dis. 2022 Feb;45(2):315-326. doi: 10.1111/jfd.13557. Epub 2021 Nov 21.
PirAB is a binary toxic protein that causes acute hepatopancreatic necrosis disease (AHPND) in shrimp. Their closest homologs, PirA -like and PirB -like proteins, are encoded by two adjacent genes on a non-pVH plasmid from a Vibrio campbellii strain. Herein, PirAB -like protein caused neither abnormalities nor death in shrimp postlarvae (Litopenaeus vannamei); furthermore, typical AHPND clinical signs were not observed. PirA -like protein corresponds to Cry toxin domain III (ligand-binding domain) and likely binds to N-acetylgalactosamine. The C-terminal and N-terminal of PirB -like resemble Cry toxin domain II (receptor-binding domain) and domain I (pore-forming domain), respectively. PirA -like and PirB -like proteins are structurally similar to PirA and PirB, respectively. Subtle structural differences between PirA -like protein and PirA appear to be involved in ligand-binding and binary protein complex formation. The difference in virulence of PirAB -like and PirAB may result from the specific binding of the protein complex to distinct host receptors. These results shed light on the potential functions and host receptors of PirAB -like proteins and their relationship with PirAB.
PirAB 是一种二元毒性蛋白，可引起虾类急性肝胰腺坏死病（AHPND）。它们最接近的同源物 PirA-样和 PirB-样蛋白，由来自副溶血弧菌菌株的非 pVH 质粒上的两个相邻基因编码。在此，PirAB-样蛋白既未引起虾幼体（凡纳滨对虾）出现异常，也未导致其死亡；此外，未观察到典型的 AHPND 临床症状。PirA-样蛋白对应于 Cry 毒素结构域 III（配体结合域），可能与 N-乙酰半乳糖胺结合。PirB-样蛋白的 C 端和 N 端分别类似于 Cry 毒素结构域 II（受体结合域）和结构域 I（孔形成域）。PirA-样和 PirB-样蛋白在结构上分别类似于 PirA 和 PirB。PirA-样蛋白与 PirA 之间的细微结构差异可能涉及配体结合和二元蛋白复合物的形成。PirAB-样和 PirAB 毒力的差异可能源于蛋白复合物与特定宿主受体的特异性结合。这些结果阐明了 PirAB-样蛋白的潜在功能和宿主受体及其与 PirAB 的关系。
