Summary for 3RWN
| Entry DOI | 10.2210/pdb3rwn/pdb |
| Descriptor | Gene 9 protein, GLUTAMIC ACID, PHOSPHATE ION, ... (4 entities in total) |
| Functional Keywords | knob, cell membrane penetration, bacteriophage sf6, viral protein |
| Biological source | Shigella phage Sf6 (Shigella flexneri bacteriophage VI) |
| Total number of polymer chains | 3 |
| Total formula weight | 51957.27 |
| Authors | Bhardwaj, A.,Cingolani, G. (deposition date: 2011-05-09, release date: 2011-06-08, Last modification date: 2024-02-28) |
| Primary citation | Bhardwaj, A.,Molineux, I.J.,Casjens, S.R.,Cingolani, G. Atomic structure of bacteriophage Sf6 tail needle knob. J.Biol.Chem., 286:30867-30877, 2011 Cited by PubMed Abstract: Podoviridae are double-stranded DNA bacteriophages that use short, non-contractile tails to adsorb to the host cell surface. Within the tail apparatus of P22-like phages, a dedicated fiber known as the "tail needle" likely functions as a cell envelope-penetrating device to promote ejection of viral DNA inside the host. In Sf6, a P22-like phage that infects Shigella flexneri, the tail needle presents a C-terminal globular knob. This knob, absent in phage P22 but shared in other members of the P22-like genus, represents the outermost exposed tip of the virion that contacts the host cell surface. Here, we report a crystal structure of the Sf6 tail needle knob determined at 1.0 Å resolution. The structure reveals a trimeric globular domain of the TNF fold structurally superimposable with that of the tail-less phage PRD1 spike protein P5 and the adenovirus knob, domains that in both viruses function in receptor binding. However, P22-like phages are not known to utilize a protein receptor and are thought to directly penetrate the host surface. At 1.0 Å resolution, we identified three equivalents of l-glutamic acid (l-Glu) bound to each subunit interface. Although intimately bound to the protein, l-Glu does not increase the structural stability of the trimer nor it affects its ability to self-trimerize in vitro. In analogy to P22 gp26, we suggest the tail needle of phage Sf6 is ejected through the bacterial cell envelope during infection and its C-terminal knob is threaded through peptidoglycan pores formed by glycan strands. PubMed: 21705802DOI: 10.1074/jbc.M111.260877 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1 Å) |
Structure validation
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