FIG. 2.

Proposed pathway for production of the 6-deoxy-5-keto-d-arabino-hexofuranose and aminocyclitol moieties of hygromycin A from glucose. The bold bonds indicate intact labeling of hygromycin A from d-[1,2-¹³C₂]glucose (low-level intact labeling of C-3 and C-4 of hygromycin was also observed). The “13” indicates labeling of the furanose ring of hygromycin A by [1-¹³C]mannose.