1. Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain.
- Author
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Parent, Kristin N, Tang, Jinghua, Cardone, Giovanni, Gilcrease, Eddie B, Janssen, Mandy E, Olson, Norman H, Casjens, Sherwood R, and Baker, Timothy S
- Subjects
Bacteriophages ,Virion ,Capsid Proteins ,Cryoelectron Microscopy ,Phylogeny ,Amino Acid Sequence ,Conserved Sequence ,Protein Structure ,Tertiary ,Protein Binding ,Models ,Molecular ,Molecular Sequence Data ,Bacteriophage ,CUS-3 ,Cryo-electron microscopy ,Virion structure ,Biological Sciences ,Agricultural and Veterinary Sciences ,Medical and Health Sciences ,Virology - Abstract
CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the "HK97-fold" shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain ("I-domain"), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently.
- Published
- 2014