Methanotroph metabolic pathways. The pMMO trimer is colored by protomer, showing its C3 symmetrical organization. sMMO is colored by subunits that comprise the complex, along with the MMO regulatory protein B (MMOB) bound (indigo) on the front and back (dashed line) sides of sMMO. MDH, methanol dehydrogenase; ICMs, intracytoplasmic membranes; PFLAs, phospholipid fatty acids; RuMP, ribulose monophosphate; CBB, Calvin-Benson-Bassham; H4MPT, tetrahydromethanopterin pathway; H4F, tetrahydrofolate pathway; FDH, formate dehydrogenase; SHMT, serine hydroxymethyltransferase; Hps, hexulose 6-phosphate synthase; RuBisCo, ribulose 1,5-bisphosphate carboxylase.