Structural basis of the substrate specificity of bifunctional isocitrate dehydrogenase kinase/phosphatase

Biochemistry. 2011 Sep 27;50(38):8103-6. doi: 10.1021/bi200809p. Epub 2011 Sep 2.

Abstract

Isocitrate dehydrogenase kinase/phosphatase (AceK) regulates entry into the glyoxylate bypass by reversibly phosphorylating isocitrate dehydrogenase (ICDH). On the basis of the recently determined structure of the AceK-ICDH complex from Escherichia coli, we have classified the structures of homodimeric NADP(+)-ICDHs to rationalize and predict which organisms likely contain substrates for AceK. One example is Burkholderia pseudomallei (Bp). Here we report a crystal structure of Bp-ICDH that exhibits the necessary structural elements required for AceK recognition. Kinetic analyses provided further confirmation that Bp-ICDH is a substrate for AceK. We conclude that the highly stringent AceK binding sites on ICDH are maintained only in Gram-negative bacteria.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Burkholderia pseudomallei / enzymology
  • Catalytic Domain
  • Dimerization
  • Escherichia coli / enzymology
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / metabolism*
  • Gram-Negative Bacteria / enzymology
  • Isocitrate Dehydrogenase / chemistry
  • Isocitrate Dehydrogenase / classification
  • Isocitrate Dehydrogenase / metabolism
  • Kinetics
  • Models, Molecular
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / metabolism*
  • Protein Conformation
  • Protein Interaction Domains and Motifs
  • Protein Structure, Quaternary
  • Substrate Specificity

Substances

  • Escherichia coli Proteins
  • Multienzyme Complexes
  • AceK protein, E coli
  • Isocitrate Dehydrogenase