A ribokinase family conserved monovalent cation binding site enhances the MgATP-induced inhibition in E. coli phosphofructokinase-2.

ABSTRACT: The presence of a regulatory site for monovalent cations that affects the conformation of the MgATP-binding pocket leading to enzyme activation has been demonstrated for ribokinases. This site is selective toward the ionic radius of the monovalent cation, accepting those larger than Na(+). Phosphofructokinase-2 (Pfk-2) from Escherichia coli is homologous to ribokinase, but unlike other ribokinase family members, presents an additional site for the nucleotide that negatively regulates its enzymatic activity. In this work, we show the effect of monovalent cations on the kinetic parameters of Pfk-2 together with its three-dimensional structure determined by x-ray diffraction in the presence of K(+) or Cs(+). Kinetic characterization of the enzyme shows that K(+) and Na(+) alter neither the kc

SUBMITTER: Baez M 

PROVIDER: S-EPMC3699746 | biostudies-literature | 2013 Jul

REPOSITORIES: biostudies-literature