Artículos de revistas
The crystal complex of phosphofructokinase-2 of Escherichia coli with fructose-6-phosphate: Kinetic and structural analysis of the allosteric atp inhibition
Fecha
2011Registro en:
Journal of Biological Chemistry, Volumen 286, Issue 7, 2018, Pages 5774-5783
00219258
1083351X
10.1074/jbc.M110.163162
Autor
Cabrera Paucar, Ricardo
Báez, Mauricio
Pereira, Humberto M.
Caniuguir, André S.
Garratt, Richard C.
Babul Cattán, Jorge
Institución
Resumen
Substrate inhibition by ATP is a regulatory feature of the phosphofructokinases isoenzymes from Escherichia coli (Pfk-1 and Pfk-2). Under gluconeogenic conditions, the loss of this regulation in Pfk-2 causes substrate cycling of fructose-6-phosphate (fructose-6-P) and futile consumption of ATP delaying growth. In the present work, we have broached the mechanism of ATP-induced inhibition of Pfk-2 from both structural and kinetic perspectives. The crystal structure of Pfk-2 in complex with fructose-6-P is reported to a resolution of 2 Å. The comparison of this structure with the previously reported inhibited form of the enzyme suggests a negative interplay between fructose-6-P binding and allosteric binding of MgATP. Initial velocity experiments show a linear increase of the apparent K0.5 for fructose-6-P and a decrease in the apparent kcat as a function of MgATP concentration. These effects occur simultaneously with the induction of a sigmoidal kinetic behavior (nH of approximately 2).