大多数研究的噬菌体(噬菌体)是陆地病毒。然而,海洋噬菌体被证明高度参与海洋监管的各个层面。他们是,然而,在很大程度上仍然被科学界忽视。通过每天诱导一半细菌种群的细胞裂解,它们对细菌生物量和进化的作用和影响,以及它们对全球生物地球化学循环的影响,是不可否认的。Cobetiamarina病毒1(Carin-1)是感染γ-原细菌C.marina的Podoviridae家族的成员。这里,我们呈现的几乎是完整的,包含衣壳的Carin-1的近原子分辨率结构,门户,和尾翼机械在3.5贝达,3.8和3.9,分别,通过低温电子显微镜(cryo-EM)测定。我们的实验结果,结合AlphaFold2(AF),使我们能够通过拟合和完善高分辨率低温EM图中的AF原子模型来获得Carin-1的近原子结构,跳过从头手动建筑的瓶颈,加快结构确定过程。我们的结构结果突出了Carin1的T7样性质,以及几个新颖的结构特征,如衣壳上存在短尖峰,让人想起对荚膜红细菌基因转移剂(RcGTA)的描述。这是,根据我们的知识,这种组装第一次被描述为噬菌体,为基因转移剂和噬菌体之间的共同进化和共享机制发光。为海洋podopage确定的第一个完整结构允许提出与原型podopageT7提出的感染机制不同的感染机制。重要性海洋在地球上的碳循环和气候调节中起着核心作用(地球上一半的二氧化碳被海洋中的浮游植物光合作用吸收,同样多的氧气被释放)。对海洋生物学生化平衡的理解是我们未来的主要目标。通过每天溶解一半的细菌种群,海洋噬菌体是这些平衡的关键参与者。尽管它们很重要,这些海洋噬菌体,到目前为止,只被研究了一点,特别是,目前缺乏结构洞察力,即使它们是理解其感染方式的分子机制的基础。我们手稿中描述的结构使我们能够提出一种与陆地T7病毒不同的感染机制,也可能允许我们,在未来,更好地了解噬菌体塑造全球生态系统的方式。
Most of studied bacteriophages (phages) are terrestrial viruses. However, marine phages are shown to be highly involved in all levels of oceanic regulation. They are, however, still largely overlooked by the scientific community. By inducing cell lysis on half of the bacterial population daily, their role and influence on the bacterial biomass and evolution, as well as their impact in the global biogeochemical cycles, is undeniable. Cobetia marina virus 1 (Carin-1) is a member of the Podoviridae family infecting the γ-protoabacteria C. marina. Here, we present the almost complete, nearly-atomic resolution structure of Carin-1 comprising capsid, portal, and tail machineries at 3.5 Å, 3.8 Å and 3.9 Å, respectively, determined by cryo-electron microscopy (cryo-EM). Our experimental results, combined with AlphaFold2 (AF), allowed us to obtain the nearly-atomic structure of Carin-1 by fitting and refining the AF atomic models in the high resolution cryo-EM map, skipping the bottleneck of de-novo manual building and speeding up the structure determination process. Our structural results highlighted the T7-like nature of Carin1, as well as several novel structural features like the presence of short spikes on the capsid, reminiscent those described for Rhodobacter capsulatus gene transfer agent (RcGTA). This is, to our knowledge, the first time such assembly is described for a bacteriophage, shedding light into the common evolution and shared mechanisms between gene transfer agents and phages. This first full structure determined for a marine podophage allowed to propose an infection mechanism different than the one proposed for the archetypal podophage T7. IMPORTANCE Oceans play a central role in the carbon cycle on Earth and on the climate regulation (half of the planet\'s CO2 is absorbed by phytoplankton photosynthesis in the oceans and just as much O2 is liberated). The understanding of the biochemical equilibriums of marine biology represents a major goal for our future. By lysing half of the bacterial population every day, marine bacteriophages are key actors of these equilibriums. Despite their importance, these marine phages have, so far, only been studied a little and, in particular, structural insights are currently lacking, even though they are fundamental for the understanding of the molecular mechanisms of their mode of infection. The structures described in our manuscript allow us to propose an infection mechanism that differs from the one proposed for the terrestrial T7 virus, and might also allow us to, in the future, better understand the way bacteriophages shape the global ecosystem.