Reversible unfolding of dimeric phosphofructokinase-2 from Escherichia coli reveals a dominant role of inter-subunit contacts for stability.
Escherichia coli phosphofructokinase-2 (Pfk-2) is a homodimer whose subunits consist of a large domain and an additional beta-sheet that provides the interfacial contacts between the subunits, creating a beta-barrel flattened-like structure with the adjacent subunit's beta-sheet. To determine how the structural organization of Pfk-2 determines its stability, the reversible unfolding of the enzyme was characterized under equilibrium conditions by enzymatic activity, circular dichroism, fluorescence and hydrodynamic measurements. Pfk-2 undergoes a cooperative unfolding/dissociation process with the accumulation of an expanded and unstructured monomeric intermediate with a marginal stability and a large solvent accessibility with respect to the native dimer.
Baez
Mauricio
M
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
Babul
Jorge
J
D002942:Circular Dichroism; D019281:Dimerization; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology*; D019791:Guanidine; D008027:Light; D025481:Phosphofructokinase-2 / Q000737:chemistry*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
D021122:Protein Subunits; D017853:Phosphotransferases (Alcohol Group Acceptor); D025481:Phosphofructokinase-2; C022534:ribokinase; D019791:Guanidine