Institute of Biotechnology and Department of Biosciences, Biocenter 2, University of Helsinki, FI-00014 Helsinki, Finland.
Proc Natl Acad Sci U S A. 2012 May 1;109(18):7079-84. doi: 10.1073/pnas.1120174109. Epub 2012 Apr 16.
The multitude of archaea and bacteria inhabiting extreme environments has only become evident during the last decades. As viruses apply a significant evolutionary force to their hosts, there is an inherent value in learning about viruses infecting these extremophiles. In this study, we have focused on one such unique virus-host pair isolated from a hypersaline environment: an icosahedral, membrane-containing double-stranded DNA virus--Salisaeta icosahedral phage 1 (SSIP-1) and its halophilic host bacterium Salisaeta sp. SP9-1 closely related to Salisaeta longa. The architectural principles, virion composition, and the proposed functions associated with some of the ORFs of the virus are surprisingly similar to those found in viruses belonging to the PRD1-adenovirus lineage. The virion structure, determined by electron cryomicroscopy, reveals that the bulk of the outer protein capsid is composed of upright standing pseudohexameric capsomers organized on a T = 49 icosahedral lattice. Our results give a comprehensive description of a halophilic virus-host system and shed light on the relatedness of viruses based on their virion architecture.
在过去的几十年中，人们才逐渐认识到，在极端环境中栖息着大量的古菌和细菌。由于病毒对其宿主施加了重要的进化压力，因此了解感染这些嗜极生物的病毒具有内在价值。在这项研究中，我们专注于从高盐环境中分离出的一对独特的病毒-宿主：一种二十面体、膜结合的双链 DNA 病毒——盐单胞菌二十面体噬菌体 1（SSIP-1）及其嗜盐宿主细菌盐单胞菌 SP9-1，它与盐单胞菌 longa 密切相关。该病毒的结构原理、病毒粒子组成以及与一些 ORF 相关的拟议功能与属于 PRD1-腺病毒谱系的病毒非常相似。通过电子 cryomicroscopy 确定的病毒粒子结构表明，大量的外壳蛋白由垂直排列的拟六聚体衣壳组成，这些衣壳在 T = 49 的二十面体晶格上组织排列。我们的研究结果全面描述了嗜盐病毒-宿主系统，并揭示了基于病毒粒子结构的病毒之间的亲缘关系。
