PRD1 bacteriophage

Grahn, M. A. Daugelavicius, R. Bamford, D. H. The small viral membrane-associated protein P32 is involved in bacteriophage PRD1 DNA entry. J. Virol. 2002,78,4866-4872. 

Fig. 1. Schematic drawings of the viruses discussed in this chapter. (A) An icosahe-dral virus with fiber proteins inserted in its pentameric vertices. The gray box denotes domains with known structures for adenovirus, reovirus, and bacteriophage PRD1, in each case containing the head domain and proximal part of the triple /8-spiral shaft domain. (B) Contractile-tailed bacteriophage T4. T4 contains three different fibrous proteins, fibritin connected to the neck, the long (bent) fibers connected to the base plate, and the short fibers also connected to the base plate. Only two of each of the trimeric fibrous proteins are shown for clarity. The gray box denotes domains with known structure for the T4 short fiber.

More recently, triple /1-spiral repeats have been identified in mammalian reovirus type 3 fiber (Chappell et al., 2002 Fig. 4A), avian reovirus fiber (Guardado Calvo et al., 2005 Fig. 4B), and bacteriophage PRD1 P5 protein (Merckel et al., 2005 Fig. 4C). In the latter two cases, it appears that only two repeats are present, just N-terminal to the head domain. Mammalian reovirus fiber contains eight putative triple /1-spiral repeats, of which three were resolved in the crystal structure (Chappell et al., 2002). 

Merckel, M. C., Huiskonen, J. T., Bamford, D. H., Goldman, A., and Tuma, R. (2005). The structure of the bacteriophage PRD1 spike sheds light on the evolution of viral capsid architecture. Mol. Cell 18, 161-170. 

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