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Publication Abstract from PubMed

The origin of viruses remains an open question. While lack of detectable sequence similarity hampers the analysis of distantly related viruses, structural biology investigations of conserved capsid protein structures facilitate the study of distant evolutionary relationships. Here we characterize the lipid-containing ssDNA temperate bacteriophage PhiCjT23, which infects Flavobacterium sp. (Bacteroidetes). We report PhiCjT23-like sequences in the genome of strains belonging to several Flavobacterium species. The virion structure determined by cryogenic electron microscopy reveals similarities to members of the viral kingdom Bamfordvirae that currently consists solely of dsDNA viruses with a major capsid protein composed of two upright beta-sandwiches. The minimalistic structure of PhiCjT23 suggests that this phage serves as a model for the last common ancestor between ssDNA and dsDNA viruses in the Bamfordvirae. Both PhiCjT23 and the related phage FLiP infect Flavobacterium species found in several environments, suggesting that these types of viruses have a global distribution and a shared evolutionary origin. Detailed comparisons to related, more complex viruses not only expand our knowledge about this group of viruses but also provide a rare glimpse into early virus evolution.

Cryo-EM structure of ssDNA bacteriophage PhiCjT23 provides insight into early virus evolution.,Kejzar N, Laanto E, Rissanen I, Abrishami V, Selvaraj M, Moineau S, Ravantti J, Sundberg LR, Huiskonen JT Nat Commun. 2022 Dec 3;13(1):7478. doi: 10.1038/s41467-022-35123-6. PMID:36463224^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.