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Publication Abstract from PubMed

Staphylococcus aureus pathogenicity island 1 (SaPI1) is a mobile genetic element that carries genes for several superantigen toxins. SaPI1 is normally stably integrated into the host genome but can become mobilized by "helper" bacteriophage 80alpha, leading to the packaging of SaPI1 genomes into phage-like transducing particles that are composed of structural proteins supplied by the helper phage but having smaller capsids. We show that the SaPI1-encoded protein gp6 is necessary for efficient formation of small capsids. The NMR structure of gp6 reveals a dimeric protein with a helix-loop-helix motif similar to that of bacteriophage scaffolding proteins. The gp6 dimer matches internal densities that bridge capsid subunits in cryo-electron microscopy reconstructions of SaPI1 procapsids, suggesting that gp6 acts as an internal scaffolding protein in capsid size determination.

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 Sep 30;412(4):710-22. Epub 2011 Jul 29. PMID:21821042^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.