9.B.78 The Minor Capsid Protein, gp7, of Bacillus subtilis Phage SPP1 (gp7) Family

Gp7 is a minor capsid protein of the Bacillus subtilis bacteriophage SPP1. Homologous proteins are found in numerous phages. Deletion of gene 7 from the SPP1 genome yielded a mutant phage (SPP1del7) with reduced burst-size. SPP1del7 infections led to normal assembly of virus particles whose morphology, DNA and protein composition was undistinguishable from wild-type virions. However, only approximately 25% of the viral particles that lack gp7 were infectious (Vinga et al., 2006). SPP1del7 particles caused a reduced depolarization of the B. subtilis membrane in infection assays suggesting a defect in virus genome traffic to the host cell. A higher number of SPP1del7 DNA ejection events led to abortive release of DNA to the culture medium when compared with wild-type infections. DNA ejection in vitro showed that no detectable gp7 is co-ejected with the SPP1 genome and that its presence in the virion correlated with anchoring of released DNA to the phage particle. The release of DNA from wild-type phages was slower than that from SPP1del7 suggesting that gp7 controls DNA exit from the virion. This feature is proposed to play a central role in supporting correct routing of the phage genome from the virion to the cell cytoplasm (Vinga et al., 2006). Antiviral agents, BIT225, benzamine, amantadine and NN-DNJ all interact with a heptameric form of p7 (Dahl et al. 2017).

gp7 facilitates the transport reaction:

Phage DNA (phage particle) → Phage DNA (host cytoplasm)

This family belongs to the .



Dahl, S., M.M. Kalita, and W.B. Fischer. (2017). Interaction of antivirals with a heptameric bundle model of the p7 protein of hepatitis C virus. Chem Biol Drug Des. [Epub: Ahead of Print]

Vinga, I., A. Dröge, A.C. Stiege, R. Lurz, M.A. Santos, R. Daugelavicius, and P. Tavares. (2006). The minor capsid protein gp7 of bacteriophage SPP1 is required for efficient infection of Bacillus subtilis. Mol. Microbiol. 61: 1609-1621.


TC#NameOrganismal TypeExample
9.B.78.1.1The (potential pore-forming minor capsid protein of B. subtilis phage SPP1, gp7. BacteriaGp7 of Bacillus subtilis phage, SPP1. (Q38442)