Fig. 4: Mechanism by which PS regulates conformational changes.

a Molecular formula of PS. b Structure and cryo-EM density of PS. c Hydrolytic activity measured by the rate of phosphate (Pi) release from WT G6PC1 and mutants solubilized in LMNG-CHS. Background activity of post-denaturation was subtracted. Results are averages of three independent measurements (n = 3), and error bars represent calculated standard error of the mean. d Overall structure of G6PC1^Pi in complex with PS. The surface electrostatic potential is shown as a translucent overlay. G6PC1^Pi is demonstrated as light pink cylinders. The structure of PS is depicted as spheres and colored by different atoms. e Conformational change of EL2 from G6PC1^G6P to G6PC1^Pi. The overall structure is represented as translucent grey surface, and PS is depicted as sticks. G6PC1^G6P and G6PC1^Pi are colored pale yellow and light pink, respectively. f Detailed interactions between PS and G6PC1^Pi. The interacting residues are shown as sticks, and PS are demonstrated in a ball-and-stick representation. The carbon atoms of PS are colored purple. g–i Comparison of interactions between the serine headgroup of PS and nearby residues in G6PC1^APO (g), G6PC1^G6P (h) and G6PC1^Pi (i). The hydrogen bonds are shown as teal dashed lines.