What's the copy number of the pBE-S vector from B. Subtilis Secretory Protein Expression System?

What's the copy number of the pBE-S vector from B. Subtilis Secretory Protein Expression System?

*High (pMSE3: 200–250 copies) (Silbersack et al. 2006),
*medium (pBE-S: 50 copies) (Leonhardt 1990), and
*low (pHB201: 5 copies) (Bron et al. 1987, 1998) copy numbers.

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