title: Regulatory network of the allosteric ATP inhibition of E. coli phosphofructokinase-2 studied by hybrid dimers.
abstract: We have proposed an allosteric ATP inhibition mechanism of Pfk-2 determining the structure of different forms of the enzyme together with a kinetic enzyme analysis. Here we complement the mechanism by using hybrid oligomers of the homodimeric enzyme to get insights about the allosteric communication pathways between the same sites or different ones located in different subunits. Kinetic analysis of the hybrid enzymes indicate that homotropic interactions between allosteric sites for ATP or between substrate sites for fructose-6-P have a minor effect on the enzymatic inhibition induced by ATP. In fact, the sigmoid response for fructose-6-P observed at elevated ATP concentrations can be eliminated even though the enzymatic inhibition is still operative. Nevertheless, leverage coupling analysis supports heterotropic interactions between the allosteric ATP and fructose-6-P binding occurring between and within each subunit.
authors: Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors: Pablo
authors: P
authors: Villalobos
authors: Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors: Francisco
authors: F
authors: Soto
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile. Electronic address: mauricio.baez@ciq.uchile.cl.
authors: Mauricio
authors: M
authors: Baez
authors: Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile. Electronic address: jbabul@u.uchile.cl.
authors: Jorge
authors: J
authors: Babul
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000494:Allosteric Regulation; D000495:Allosteric Site; D001665:Binding Sites / Q000235:genetics; D055162:Biocatalysis / Q000187:drug effects; D003198:Computer Simulation; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005636:Fructosephosphates / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D015394:Molecular Structure; D009154:Mutation; D025481:Phosphofructokinase-2 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D000072417:Protein Domains; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D005636:Fructosephosphates; D021122:Protein Subunits; C027618:fructose-6-phosphate; D000255:Adenosine Triphosphate; D025481:Phosphofructokinase-2
keywords: Allosteric communication; Allosteric regulation; Hybrid enzyme dimers; Phosphofructokinase-2; Subunits interactions