Nuclear magnetic resonance studies of fructose 2,6-bisphosphate and adenosine 5'-monophosphate interaction with bovine liver fructose-1,6-biphosphatase.
1H and 31P nuclear magnetic resonance was used to investigate the interaction of AMP and fructose 2,6-bisphosphate (Fru-2,6-P2) with bovine liver fructose-1,6-bisphosphatase. Mn2+ bound to fructose-1,6-bisphosphatase was used as a paramagnetic probe to map the active and AMP allosteric sites of fructose-1,6-bisphosphatase. Distances between enzyme-bound Mn2+ and the phosphorus atoms at C-6 of fructose-6-P and alpha-methyl-D-fructofuranoside 1,6-bisphosphate were identical, and the enzyme-Mn to phosphorus distance determined for the C-6 phosphorus atom of Fru-2,6-P2 was very similar to these values. Likewise, the enzyme-Mn to phosphorus distances for Pi, the C-1 phosphorus atom of alpha-methyl-D-fructofuranoside 1,6-bisphosphate, and the C-2 phosphorus atom of Fru-2,6-P2 agreed within 0.5 A. The distance between enzyme-bound Mn2+ and the phosphorus atom of AMP was significantly shorter than the distances obtained for any of the aforementioned ligands, but the presence of Fru-2,6-P2 caused the enzyme-Mn to phosphorus distance for AMP to lengthen markedly. NMR line broadening of AMP protons was studied at various temperatures. The dissociation rate constant was found to be greater than 20 s-1. It was concluded that Fru-2,6-P2 strongly affects the interaction of AMP with fructose-1,6-bisphosphatase and that the sugar most likely acts at the active site of the enzyme.
Ganson
N J
NJ
Fromm
H J
HJ
D000249:Adenosine Monophosphate / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D006597:Fructose-Bisphosphatase / Q000378:metabolism*; D005635:Fructosediphosphates / Q000378:metabolism*; D006598:Hexosediphosphates / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy
D005635:Fructosediphosphates; D006598:Hexosediphosphates; D000249:Adenosine Monophosphate; C027652:fructose 2,6-diphosphate; D006597:Fructose-Bisphosphatase