Uncoupling the MgATP-induced inhibition and aggregation of Escherichia coli phosphofructokinase-2 by C-terminal mutations.
Binding of MgATP to an allosteric site of Escherichia coli phosphofructokinase-2 (Pfk-2) provoked inhibition and a dimer-tetramer (D-T) conversion of the enzyme. Successive deletions of up to 10 residues and point mutations at the C-terminal end led to mutants with elevated K(Mapp) values for MgATP which failed to show the D-T conversion, but were still inhibited by the nucleotide. Y306 was required for the quaternary packing involved in the D-T conversion and the next residue, L307, was crucial for the ternary packing necessary for the catalytic MgATP-binding site. These results show that the D-T conversion could be uncoupled from the conformational changes that lead to the MgATP-induced allosteric inhibition.
Baez
Mauricio
M
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Merino
Felipe
F
Astorga
Guadalupe
G
Babul
Jorge
J
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000494:Allosteric Regulation; D000495:Allosteric Site; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D025481:Phosphofructokinase-2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D011487:Protein Conformation; D017384:Sequence Deletion
D029968:Escherichia coli Proteins; D000255:Adenosine Triphosphate; D025481:Phosphofructokinase-2