Molecular architecture and structural basis of allosteric regulation of eukaryotic phosphofructokinases

Eukaryotic ATP-dependent 6-phosphofructokinases (Pfks) differ from their bacterial counterparts in a much more complex structural organization and allosteric regulation. Pichia pastoris Pfk (PpPfk) is, with ∼1 MDa, the most complex and probably largest eukaryotic Pfk. We have determined the crystal structure of full-length PpPfk to 3.05 A resolution in the T state. PpPfk forms a (αβγ)4 dodecamer of D2 symmetry with dimensions of 161 × 157 × 233 A mainly via interactions of the α chains. The N-terminal domains of the α and β chains have folds that are distantly related to glyoxalase I, but the active sites are no longer functional. Interestingly, these domains located at the 2 distal ends of this protein along the long 2-fold axis form a (αβ)2 dimer as does the core Pfk domains; however, the domains are swapped across the tetramerization interface. In PpPfk, the unique γ subunit participates in oligomerization of the αβ chains. This modulator protein was acquired from an ancient S-adenosylmethionine-depend...