Subramanian Sundharraman, Kerns Hailey R, Braverman Samantha G, Doore Sarah M
Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.
Commun Biol. 2025 Feb 12;8(1):222. doi: 10.1038/s42003-025-07668-x.
Bacteriophage Sf14 infects the human pathogen Shigella flexneri. A previous low-resolution structure suggested the presence of a decoration protein on its T = 9 icosahedral capsid. Here, we determined high-resolution structures of the Sf14 capsid and neck, along with a moderate-resolution structure of the whole Sf14 tail and baseplate. These structures indicate the capsid has not one, but two different types of decoration proteins: a trimeric β-tulip lattice that covers the entire capsid and a set of Hoc-like proteins that bind preferentially to hexamers at the quasi-3-fold axes of symmetry. The neck also contains two sets of whiskers oriented in opposite directions, and the tail has two types of long tail fibers which may bind different receptors. Based on homology and phylogenetic analysis, Sf14 may be the product of multiple horizontal gene transfer events. The structures presented here can be used to investigate further hypotheses of phage structure-function relationships and structural diversity.
噬菌体Sf14感染人类病原体福氏志贺菌。先前的低分辨率结构表明其T = 9二十面体衣壳上存在一种装饰蛋白。在此，我们确定了Sf14衣壳和颈部的高分辨率结构，以及整个Sf14尾部和基板的中等分辨率结构。这些结构表明衣壳并非只有一种，而是有两种不同类型的装饰蛋白：一种三聚体β-郁金香晶格覆盖整个衣壳，还有一组类Hoc蛋白优先结合在准三重对称轴处的六聚体上。颈部还包含两组方向相反的须状物，尾部有两种类型的长尾纤维，可能结合不同的受体。基于同源性和系统发育分析，Sf14可能是多次水平基因转移事件的产物。本文展示的结构可用于进一步研究噬菌体结构-功能关系和结构多样性的假设。
