title: The C-terminal domain of the Uup protein is a DNA-binding coiled coil motif.
abstract: The bacterial Uup protein belongs to the REG subfamily of soluble ATP-binding cassette (ABC) ATPases, and is implicated in precise excision of transposons. In Escherichia coli, the uup gene encodes a 72 kDa polypeptide that comprises two ABC domains, separated by a linker region, and a 12kDa C-terminal domain (CTD). Uup binds double-stranded DNA with no sequence specificity, and we previously demonstrated that the CTD domain is a crucial region that participates in DNA-binding activity. We report herein the NMR structure of Uup CTD, consisting of an intramolecular antiparallel two-stranded coiled coil motif. Structural comparison with analogous coiled coil domains reveals that Uup CTD contains an atypical 3(10)-helix in the α-hairpin region that contributes to the hydrophobic core. Using NMR titration experiments, we identified residues of the CTD domain involved in the binding to double-stranded DNA. These residues are located on two opposite surfaces at the base of the coiled coil, formed by the N- and C-terminal extremities, where a strictly conserved proline residue induces an overwinding of the coiled coil. Finally, preliminary analysis of NMR spectra recorded on distinct Uup constructs precludes a fully flexible positioning of the CTD domain in full-length Uup. These structural data are the first reported for a non-ATPase domain within ABC REG subfamily.
authors.affiliation: UPMC Université Paris 06, Laboratoire des BioMolécules UMR 7203, 4 place Jussieu, 75005 Paris, France. ludovic.carlier@upmc.fr
authors.forename: Ludovic
authors.initials: L
authors.lastname: Carlier
authors.forename: A Sander
authors.initials: AS
authors.lastname: Haase
authors.forename: Monica Y
authors.initials: MY
authors.lastname: Burgos Zepeda
authors.forename: Elie
authors.initials: E
authors.lastname: Dassa
authors.forename: Olivier
authors.initials: O
authors.lastname: Lequin
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D001665:Binding Sites; D004269:DNA, Bacterial / Q000737:chemistry* / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000737:chemistry* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D040681:Structural Homology, Protein
chemical_list: D018528:ATP-Binding Cassette Transporters; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C105795:Uup protein, E coli