title: Structural basis of the substrate specificity of bifunctional isocitrate dehydrogenase kinase/phosphatase.
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.
authors.affiliation: Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Yates
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Edwards
authors.forename: Cassie M
authors.initials: CM
authors.lastname: Bryan
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Stein
authors.forename: Wesley C
authors.initials: WC
authors.lastname: Van Voorhis
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Myler
authors.forename: Lance J
authors.initials: LJ
authors.lastname: Stewart
authors.forename: Jimin
authors.initials: J
authors.lastname: Zheng
authors.forename: Zongchao
authors.initials: Z
authors.lastname: Jia
mesh_terms: D016957:Burkholderia pseudomallei / Q000201:enzymology; D020134:Catalytic Domain; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000201:enzymology; D007521:Isocitrate Dehydrogenase / Q000737:chemistry / Q000145:classification / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; C548023:AceK protein, E coli; D007521:Isocitrate Dehydrogenase