An early divergence in evolution has resulted in two prokaryotic domains, the Bacteria and the Archaea. Whereas the central metabolic routes of bacteria and eukaryotes are generally well-conserved, variant pathways have developed in Archaea involving several novel enzymes with a distinct control. A spectacular example of convergent evolution concerns the glucose-degrading pathways of saccharolytic archaea. The identification, characterization and comparison of the glycolytic enzymes of a variety of phylogenetic lineages have revealed a mosaic of canonical and novel enzymes in the archaeal variants of the Embden–Meyerhof and the Entner–Doudoroff pathways. By means of integrating results from biochemical and genetic studies with recently obtained comparative and functional genomics data, the structure and function of the archaeal glycolytic routes, the participating enzymes and their regulation are re-evaluated.
Abbreviations used: AOR, aldehyde oxidoreductase; ED, Entner–Doudoroff; EM, Embden–Meyerhof; FBA, fructose-1,6-bisphosphate aldolase; FBP, fructose-1,6-bisphosphatase; FOR, formaldehyde ferredoxin oxidoreductase; GAP, glyceraldehyde 3-phosphate; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GAPN, NAD+-dependent GAPDH; GAPOR, glyceraldehyde-3-phosphate ferredoxin oxidoreductase; GLK, glucokinase; KDG, 2-keto-3-deoxygluconate; KDPG, 2-keto-3-deoxy-6-phosphogluconate; LDH, lactate dehydrogenase; ORF, open reading frame; PEP, phosphoenolpyruvate; PFK, phosphofructokinase; PFKB, minor PFK; PGI, phosphoglucose isomerase; PGK, phosphoglycerate kinase; PGM, phosphoglycerate mutase; PP, pentose phosphate; PPS, PEP synthase; PTS, phosphotransferase system; PYK, pyruvate kinase; SIS, sugar isomerase; Topt, optimum growth temperature; TIM, triosephosphate isomerase.
Present address: DSM Research, A. Fleminglaan 1, 2613 AX Delft, The Netherlands