SAPIS-gp6 is a family of proteins produced from the pathogenicity island SAPI1 in pathogenic Staphylococcus aureus. This is a mobile genetic element that carries genes for several superantigen toxins. SAPIS-gp6 is a dimeric protein produced from the pathogenicity island with a helix-loop-helix motif similar to that of bacteriophage scaffolding proteins. It is thought to determine the size of the capsids of distribution of the SAPI1 genome as it acts as an internal scaffolding protein during capsid size determination [1].

1: The Staphylococcus aureus pathogenicity island 1 protein gp6 functions as an internal scaffold during capsid size determination. Dearborn AD, Spilman MS, Damle PK, Chang JR, Monroe EB, Saad JS, Christie GE, Dokland T; J Mol Biol. 2011;412:710-722. PMID:21821042