Goulet Adeline, Mahony Jennifer, Cambillau Christian, van Sinderen Douwe
Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université-CNRS, UMR 7255, 13288 Marseille, France.
School of Microbiology, University College Cork, T12 YN60 Cork, Ireland.
Microorganisms. 2022 Nov 16;10(11):2278. doi: 10.3390/microorganisms10112278.
Bacteriophages, or phages, are the most abundant biological entities on Earth. They possess molecular nanodevices to package and store their genome, as well as to introduce it into the cytoplasm of their bacterial prey. Successful phage infection commences with specific recognition of, and adhesion to, a suitable host cell surface. Adhesion devices of siphophages infecting Gram-positive bacteria are very diverse and remain, for the majority, poorly understood. These assemblies often comprise long, flexible, and multi-domain proteins, which limit their structural analyses by experimental approaches. The protein structure prediction program AlphaFold2 is exquisitely adapted to unveil structural and functional details of such molecular machineries. Here, we present structure predictions of adhesion devices from siphophages belonging to the P335 group infecting spp., one of the most extensively applied lactic acid bacteria in dairy fermentations. The predictions of representative adhesion devices from types I-IV P335 phages illustrate their very diverse topology. Adhesion devices from types III and IV phages share a common topology with that of p2, with a receptor binding protein anchored to the virion by a distal tail protein loop. This suggests that they exhibit an activation mechanism similar to that of phage p2 prior to host binding.
噬菌体，或称 phages，是地球上数量最为丰富的生物实体。它们拥有分子纳米装置来包装和存储其基因组，并将其导入细菌猎物的细胞质中。成功的噬菌体感染始于对合适宿主细胞表面的特异性识别和黏附。感染革兰氏阳性菌的长尾噬菌体的黏附装置多种多样，而且大多数情况下人们对其了解甚少。这些组件通常由长的、灵活的多结构域蛋白质组成，这限制了通过实验方法对其进行结构分析。蛋白质结构预测程序AlphaFold2非常适合揭示此类分子机器的结构和功能细节。在此，我们展示了属于P335组的感染 spp.（乳制品发酵中应用最广泛的乳酸菌之一）的长尾噬菌体黏附装置的结构预测。来自I-IV型P335噬菌体的代表性黏附装置的预测结果表明它们具有非常多样的拓扑结构。III型和IV型噬菌体的黏附装置与噬菌体p2具有共同的拓扑结构，其受体结合蛋白通过远端尾蛋白环锚定在病毒体上。这表明它们在宿主结合之前表现出与噬菌体p2类似的激活机制。
