Involved in the biosynthesis of the antifungal agent validamycin A (PubMed:16725283). Catalyzes the final attachment of glucose from UDP-alpha-D-glucose to validoxylamine A to yield validamycin A (By similarity). UDP-alpha-D-glucose + validoxylamine A = H(+) + UDP + validamycin A Instead of having the common DXD motif at the position 130-132, it contains a DTG sequence, which may provide greater metal ion binding flexibility. Belongs to the glycosyltransferase 2 family.