Figure 1.

Proposed model for the role of TadD in TAG metabolism in R. opacus PD630. Under high nitrogen conditions (depicted on the left) glyceraldehyde 3-phosphate is metabolized to 3-phosphoglycerate by the canonical glyceraldehyde 3-phosphate dehydrogenase GapA and the phosphoglycerate kinase Pgk yielding NADH and ATP. We propose that under nitrogen limiting conditions G3P is metabolized to 3-phosphoglycerate by the non-phosphorylating, NAD(P)⁺-dependent glyceraldehyde 3-phosphate dehydrogenase TadD yielding NAD(P)H, a key redox molecule in fatty acid metabolism.