Fig. 1.

Candidate pathways supporting phosphoglycolate salvage in C. necator; 2PG is first dephosphorylated to glycolate and then oxidized, by the glycolate dehydrogenase complex, to give glyoxylate. Glyoxylate can be further metabolized via four routes: the C₂ cycle (i.e., the plant phosphoglycolate salvage pathway), the glycerate pathway, the oxalyl-CoA decarboxylation pathway, and malate cycle. The latter two routes completely oxidize glycoxylate to CO₂. Note that that malate cycle may also proceed via oxidation of malate to oxaloacetate, which can be converted to pyruvate either directly or via phosphoenolpyruvate. AceB, malate synthase; ApbA2, CoA-acylating glyoxylate dehydrogenase; CbbZ2, CbbZp, 2-phosphoglycolate phosphatase; FdsABDG, formate dehydrogenase complex; Frc, formyl-CoA transferase; Gcl, glyoxylate carboligase; GcvTHP, glycine cleavage systems; GlcDEF, glycolate dehydrogenase complex; GlyA, serine hydroxymethyltransferase; HprA, hydroxypyruvate reductase; Hyi2, hydroxypyruvate isomerase; MaeA, malic enzyme A; MaeB, malic enzyme B; Oxc, oxalyl-CoA decarboxylase; PdhA1,2, PdhB, PdhL, pyruvate dehydrogenase complex; Pgam1,2, phosphoglycerate mutatase; Rubisco, Ribulose-bisphosphate carboxylase/oxygenase; THF, tetrahydrofolate; Tsr, tartronate semialdehyde reductase; TtuD1, glycerate kinase.