Protein Domain : Gp9-like superfamily IPR036240

Type	Homologous_superfamily
Description	Members of this entry are similar to gene products 9 (gp9) and 10 (gp10) of bacteriophage T4. Both proteins are components of the viral baseplate [ ]. 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 β-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 β-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 []. Together with gp11, gp10 initiates the assembly of wedges that then go on to associate with a hub to form the viral baseplate [].
Short Name	Gp9-like_sf