title: Structural basis of nucleic-acid recognition and double-strand unwinding by the essential neuronal protein Pur-alpha.
abstract: The neuronal DNA-/RNA-binding protein Pur-alpha is a transcription regulator and core factor for mRNA localization. Pur-alpha-deficient mice die after birth with pleiotropic neuronal defects. Here, we report the crystal structure of the DNA-/RNA-binding domain of Pur-alpha in complex with ssDNA. It reveals base-specific recognition and offers a molecular explanation for the effect of point mutations in the 5q31.3 microdeletion syndrome. Consistent with the crystal structure, biochemical and NMR data indicate that Pur-alpha binds DNA and RNA in the same way, suggesting binding modes for tri- and hexanucleotide-repeat RNAs in two neurodegenerative RNAopathies. Additionally, structure-based in vitro experiments resolved the molecular mechanism of Pur-alpha's unwindase activity. Complementing in vivo analyses in Drosophila demonstrated the importance of a highly conserved phenylalanine for Pur-alpha's unwinding and neuroprotective function. By uncovering the molecular mechanisms of nucleic-acid binding, this study contributes to understanding the cellular role of Pur-alpha and its implications in neurodegenerative diseases.
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Weber
authors.affiliation: Department of Human Genetics, Emory University, Atlanta, United States.
authors.forename: Han
authors.initials: H
authors.lastname: Bao
authors.affiliation: Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Munich, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Hartlmüller
authors.affiliation: Department of Human Genetics, Emory University, Atlanta, United States.
authors.forename: Zhiqin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.
authors.forename: Almut
authors.initials: A
authors.lastname: Windhager
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Janowski
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.|Center for Integrated Protein Science Munich, Department of Chemistry, Technische Universität München, Munich, Germany.|Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria.|Omics Center Graz, BioTechMed Graz, Graz, Austria.
authors.forename: Tobias
authors.initials: T
authors.lastname: Madl
authors.affiliation: Department of Human Genetics, Emory University, Atlanta, United States.
authors.forename: Peng
authors.initials: P
authors.lastname: Jin
authors.affiliation: Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany.|Department Cell Biology, Biomedical Center of the Ludwig-Maximilians-University München, Planegg-Martinsried, Germany.
authors.forename: Dierk
authors.identifier: http://orcid.org/0000-0002-5589-369X
authors.initials: D
authors.lastname: Niessing
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D004277:DNA, Single-Stranded / Q000737:chemistry* / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins / Q000737:chemistry* / Q000378:metabolism*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004277:DNA, Single-Stranded; D029721:Drosophila Proteins; C545199:Pur-alpha protein, Drosophila; D014157:Transcription Factors
keywords: 5q31.3 microdeletion syndrome; <i>d. melanogaster</i>; <i>e. coli</i>; ALS; DNA unwinding; DNA-/RNA-protein interaction; FXTAS; X-ray crystallography; biochemistry; biophysics; structural biology