Baseplate structural protein Gp9/Gp10 (IPR008987)

Short name: Baseplate_struct_prot_Gp9/10

Overlapping homologous superfamilies


Family relationships


The members of this family are similar to gene products 9 (gp9) and 10 (gp10) of bacteriophage T4. Both proteins are components of the viral baseplate [PMID: 12626685]. Gp9 connects the long tail fibres of the virus to the baseplate and triggers tail contraction after viral attachment to a host cell. The protein is active as a trimer, with each monomer being composed of three domains. The N-terminal domain consists of an extended polypeptide chain and two alpha helices. The alpha1 helix from each of the three monomers in the trimer interacts with its counterparts to form a coiled-coil structure. The middle domain is a seven-stranded beta-sandwich that is thought to be a novel protein fold. The C-terminal domain is thought to be essential for gp9 trimerisation and is organised into an eight- stranded antiparallel beta-barrel, which was found to resemble the 'jelly roll' fold found in many viral capsid proteins. The long flexible region between the N-terminal and middle domains may be required for the function of gp9 to transmit signals from the long tail fibres [PMID: 10545330]. Together with gp11, gp10 initiates the assembly of wedges that then go on to associate with a hub to form the viral baseplate [PMID: 12626685].

GO terms

Biological Process

GO:0019076 viral release from host cell

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0098025 virus tail, baseplate

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.