title: Folding kinetic pathway of phosphofructokinase-2 from Escherichia coli: a homodimeric enzyme with a complex domain organization.
abstract: Phosphofructokinase-2 is a 66 kD homodimer whose subunits are associated by means of a bimolecular domain, the β-clasp, which is linked to the larger portion of each subunit by a reentrant chain topology. To investigate how this structural organization determines the folding pathway of Pfk-2, unfolding and folding kinetic experiments were performed. The folding pathway shows an unstructured monomeric intermediate and that most part of the dimer structure is reached as a slow concerted folding/association step with a quite folded transition state in terms of solvent exposure. Unfolding kinetics show a transient intermediate, probably a partially unfolded dimer. We propose that these characteristics arise by a mutual constrain between the large domain and the β-clasp domain imposed by their interrupted chain connectivity.
authors.affiliation: Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Baez
authors.forename: Christian A M
authors.initials: CA
authors.lastname: Wilson
authors.forename: Jorge
authors.initials: J
authors.lastname: Babul
mesh_terms: D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D025481:Phosphofructokinase-2 / Q000737:chemistry*; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D058767:Protein Unfolding; D013816:Thermodynamics
chemical_list: D029968:Escherichia coli Proteins; D025481:Phosphofructokinase-2