FIGURE 4.

Model predictions of the central metabolism inferred from the B42 genome sequence. Important energy generating reactions are shown expanded on the lower left corner. Carbon derived from methane is either completely oxidized to CO₂ (dashed line) or is assimilated through the RuMP pathway into the glycolysis and TCA cycle. A proposed cellular ultrastructure is shown in the top right. The genome also encodes genes to the construction of pili, flagella and for the accumulation of polyphosphate and glycogen granules. Abbreviations: G6P, glucose 6-phosphate; G1,5LP, 6-phospho D-glucono-1,5-lactone; 6GP, gluconate 6-phosphate; Ru5P, ribulose 5-phosphate; Ri5P, ribose 5-phosphate; X5P, xylulose 5-phosphate; GAP, glyceraldehyde 3-phosphate; S7P, sedoheptulose 7-phosphate; F6P, fructofuranose 6-phosphate; E4P, erythrose 4-phosphate; F1,6P, fructose 1,6-bisphosphate; 3PGA, 3-phospho-D-glycerate; 2PGA, 2-phospho-D-glycerate; PEP, phosphoenolpyruvate; CH₂ = H₄MPT, 5,10-methylene-tetrahydromethanopterin; CH₂≡H₄MPT, 5,10-methenyltetrahydromethanopterin; CHO-H₄MPT, 5-formyl-tetrahydromethanopterin.