title: The structure of bradyzoite-specific enolase from Toxoplasma gondii reveals insights into its dual cytoplasmic and nuclear functions.
abstract: In addition to catalyzing a central step in glycolysis, enolase assumes a remarkably diverse set of secondary functions in different organisms, including transcription regulation as documented for the oncogene c-Myc promoter-binding protein 1. The apicomplexan parasite Toxoplasma gondii differentially expresses two nuclear-localized, plant-like enolases: enolase 1 (TgENO1) in the latent bradyzoite cyst stage and enolase 2 (TgENO2) in the rapidly replicative tachyzoite stage. A 2.75 Å resolution crystal structure of bradyzoite enolase 1, the second structure to be reported of a bradyzoite-specific protein in Toxoplasma, captures an open conformational state and reveals that distinctive plant-like insertions are located on surface loops. The enolase 1 structure reveals that a unique residue, Glu164, in catalytic loop 2 may account for the lower activity of this cyst-stage isozyme. Recombinant TgENO1 specifically binds to a TTTTCT DNA motif present in the cyst matrix antigen 1 (TgMAG1) gene promoter as demonstrated by gel retardation. Furthermore, direct physical interactions of both nuclear TgENO1 and TgENO2 with the TgMAG1 gene promoter are demonstrated in vivo using chromatin immunoprecipitation (ChIP) assays. Structural and biochemical studies reveal that T. gondii enolase functions are multifaceted, including the coordination of gene regulation in parasitic stage development. Enolase 1 provides a potential lead in the design of drugs against Toxoplasma brain cysts.
authors.affiliation: Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA.
authors.forename: Jiapeng
authors.initials: J
authors.lastname: Ruan
authors.affiliation: Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Université Lille Nord de France, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mouveaux
authors.affiliation: Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA.
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Light
authors.affiliation: Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA.
authors.forename: George
authors.initials: G
authors.lastname: Minasov
authors.affiliation: Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA.
authors.forename: Wayne F
authors.initials: WF
authors.lastname: Anderson
authors.affiliation: Center for Infection and Immunity of Lille, CNRS UMR 8204, INSERM U1019, Institut Pasteur de Lille, Université Lille Nord de France, France.
authors.forename: Stanislas
authors.initials: S
authors.lastname: Tomavo
authors.affiliation: Center for Structural Genomics of Infectious Diseases, Northwestern University, 320 E. Superior Street, Morton 7-601, Chicago, IL 60611, USA.
authors.forename: Huân M
authors.initials: HM
authors.lastname: Ngô
mesh_terms: D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000201:enzymology / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014122:Toxoplasma / Q000201:enzymology / Q000235:genetics
chemical_list: D009687:Nuclear Proteins; D015800:Protozoan Proteins; D010751:Phosphopyruvate Hydratase
keywords: brain parasite; central nervous system; chronic infection; differentiation; moonlighting protein