Phosphorylation- and ligand-induced conformational changes of rat liver fructose-1,6-bisphosphatase.
The effects of cyclic AMP-dependent phosphorylation on the structural properties of rat liver fructose-1,6-bisphosphatase were investigated by uv difference spectroscopy and circular dichroism. The incorporation of 4 mol of phosphate per mole of fructose-1,6-bisphosphatase induces a significant increase in the alpha-helix content of the enzyme without affecting its spectrophotometric properties. The addition of fructose 1,6-bisphosphate or fructose 2,6-bisphosphate also affects the conformation of the enzyme. However, both the phosphorylated and the nonphosphorylated forms exhibit similar ligand-induced conformational changes. These results show that cyclic AMP-dependent phosphorylation of fructose-1,6-bisphosphatase induces a specific conformational change. They also suggest that this modification does not alter the interaction of the enzyme protein with fructose 1,6-bisphosphate and fructose 2,6-bisphosphate.
D000494:Allosteric Regulation; D000818:Animals; D002942:Circular Dichroism; D000242:Cyclic AMP / Q000502:physiology; D006597:Fructose-Bisphosphatase / Q000378:metabolism; D008024:Ligands; D008099:Liver / Q000201:enzymology*; D008297:Male; D010750:Phosphoproteins; D010766:Phosphorylation; D011487:Protein Conformation; D051381:Rats; D013056:Spectrophotometry, Ultraviolet
D008024:Ligands; D010750:Phosphoproteins; D000242:Cyclic AMP; D006597:Fructose-Bisphosphatase