Proposal of synthesis of mayamycin

Johannes Imhoff and co-workers at IFM-GEOMAR inn Germany have isolated a polyketide that had an IC50 value of 0.3 micromolar against HT-29 (colon adenocarcinoma) cell lines.

preparation of derivatives of Calicheamicin by enzyme ？

1. The gene for the biosynthesis of calicheamicin is known. As I can remember, the calicheamicinone is constructed and attached to a sugar by an enzyme.
2. Calicheamicin is cheap by biosynthesis. calicheamicinone is difficult to make by chemical synthesis.
3. no known way to cleave Calicheamicinone from calicheamicin.

So is it possible to make new derivatives by mixing a new sugar with calicheamicin in the presense of some enzymes ?