Fig. 2: cryoEM structures of PFKL tetramers and filaments in the T-state.

a CryoEM structure of the consensus PFKL tetramer bound to ATP and fructose 1,6-bisphosphate (F1,6BP), colored by monomer. Monomer A is also colored by domain. Insets show the various ligand binding sites. b Comparison of the catalytic domain conformation of the ATP- and F1,6BP-bound structure (blue) with the R-state PFKL structure (green). Structures are aligned on the catalytic domain of subunit A. ADP and fructose 6-phosphate (F6P) from the R-state structure are shown in the active site. c Comparison of the F6P binding site in the R-state (green) and T-state (blue) structures. The binding site involves residues from the catalytic domains of two monomers (A and B). d Comparison of monomer conformations in the R-state (green) and T-state (blue) structures. Structures are aligned on their catalytic domains (lighter shades). The C-terminus (yellow) bridges across the regulatory and catalytic domains in the T-state conformation. Lower panel shows the isolated density of the C-terminus from the T-state cryoEM map. e CryoEM structure of the T-state PFKL filament, colored by monomer. Circles show zoomed-in views of filament interfaces 1 and 2. Panels at right show comparisons to interfaces 1 and 2 in the R-state structure. Inward rotation of the catalytic domain at interface 2 in the R-state would produce a clash with the C-terminus at the position observed in the T-state structure.