Abstract 1640 Interaction of NADP+ and NAD-capped RNA with Wildtype and Mutant Human Glucose-6-Phosphate Dehydrogenase

The recent discovery that RNA polymerases frequently initiate synthesis with co-enzymes like nicotinamide adenine dinucleotide (NAD+), which then serve as atypical cap-like structures, has inspired the search for enzymes that might use NAD-capped RNA as a substrate. One possible candidate is human glucose-6-phosphate dehydrogenase (hG6PD) because hG6PD has two distinct NADP+ bindings. One site binds the catalytic NADP+ adjacent to glucose-6 phosphate (G6P). The second site is far from G6P, and the bound “structural” NADP+ has been proposed to stabilize the G6PD oligomer.