Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA.
Virology. 2011 Jan 20;409(2):319-27. doi: 10.1016/j.virol.2010.10.030. Epub 2010 Nov 10.
Assembly of dsDNA bacteriophage is a precisely programmed process. Potential roles of host cell components in phage assembly haven't been well understood. It was previously reported that two unidentified proteins were present in bacteriophage Sf6 virion (Casjens et al, 2004, J.Mol.Biol. 339, 379-394, Fig. 2A). Using tandem mass spectrometry, we have identified the two proteins as outer membrane proteins (OMPs) OmpA and OmpC from its host Shigella flexneri. The transmission electron cryo-microscopy structure of Sf6 shows significant density at specific sites at the phage capsid inner surface. This density fit well with the characteristic beta-barrel domains of OMPs, thus may be due to the two host proteins. Locations of this density suggest a role in Sf6 morphogenesis reminiscent of phage-encoded cementing proteins. These data indicate a new, OMP-related phage:host linkage, adding to previous knowledge that some lambdoid bacteriophage genomes contain OmpC-like genes that express phage-encoded porins in the lysogenic state.
噬菌体 dsDNA 的组装是一个精确编程的过程。宿主细胞成分在噬菌体组装中的潜在作用还没有被很好地理解。先前的研究报告称，噬菌体 Sf6 病毒粒子中存在两种未鉴定的蛋白质（Casjens 等人，2004 年，J.Mol.Biol. 339, 379-394, 图 2A）。我们使用串联质谱法鉴定这两种蛋白质为其宿主福氏志贺菌的外膜蛋白（OMP）OmpA 和 OmpC。Sf6 的透射电子 cryo-microscopy 结构显示在噬菌体衣壳内表面的特定位置有明显的密度。这种密度与 OMP 的特征β桶结构域非常吻合，因此可能是由于这两种宿主蛋白。该密度的位置表明其在 Sf6 形态发生中的作用类似于噬菌体编码的粘结蛋白。这些数据表明了一种新的、与 OMP 相关的噬菌体：宿主联系，增加了先前的知识，即一些 lambdoid 噬菌体基因组包含 OmpC 样基因，在溶原状态下表达噬菌体编码的孔蛋白。
