May enhance ubiquitin ligase activity of RING-type zinc finger-containing E3 ubiquitin-protein ligases. Proposed to act through recruitment and/or stabilization of the Ubl-conjugating enzyme (E2) at the E3:substrate complex. Cap8A Protein, S. aureus, Recombinant (His) is expressed in E. coli expression system with N-10xHis tag. The predicted molecular weight is 26.4 kDa and the accession number is O15479.