title: Structural study of the response regulator HupR from Rhodobacter capsulatus. Electron microscopy of two-dimensional crystals on a nickel-chelating lipid.
abstract: Two-dimensional crystals of the histidine-tagged-HupR protein, a transcriptional regulator from the photosynthetic bacterium Rhodobacter capsulatus, were obtained upon specific interaction with a Ni2+-chelated lipid monolayer. HupR is a response regulator of the NtrC family; it activates the transcription of the structural genes, hupSLC, of the [NiFe]hydrogenase. The lipid (Ni-NTA-DOGA) uses the metal chelator nitrilotriacetic group as the hydrophilic headgroup and contains unsaturated oleyl tails to provide the fluidity necessary for two-dimensional protein crystallization. A projection map of the full-length protein at 18 A resolution was generated by analysing electron microscopy micrographs of negatively stained crystals. The HupR protein appeared to be dimeric and revealed a characteristic "propeller-like" motif. Each monomer forms an L-shaped structure.
authors.affiliation: Institut de Biologie Structurale Jean-Pierre Ebel (CEA-CNRS), 41 av. des Martyrs, Grenoble cedex 1, 38027, France.
authors.forename: C
authors.initials: C
authors.lastname: Vénien-Bryan
authors.forename: F
authors.initials: F
authors.lastname: Balavoine
authors.forename: B
authors.initials: B
authors.lastname: Toussaint
authors.forename: C
authors.initials: C
authors.lastname: Mioskowski
authors.forename: E A
authors.initials: EA
authors.lastname: Hewat
authors.forename: B
authors.initials: B
authors.lastname: Helme
authors.forename: P M
authors.initials: PM
authors.lastname: Vignais
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D002614:Chelating Agents / Q000138:chemical synthesis; D003460:Crystallization; D003461:Crystallography / Q000379:methods*; D004268:DNA-Binding Proteins; D019281:Dimerization; D006639:Histidine; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008055:Lipids; D008854:Microscopy, Electron / Q000379:methods*; D010455:Peptides; D011993:Recombinant Fusion Proteins; D016354:Rhodobacter capsulatus / Q000737:chemistry; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: C109930:2-(bis-carboxymethylamino)-6-(2-(1,3-di-O-oleylglyceroxy)acetylamino)hexanoic acid nickel(II); D001426:Bacterial Proteins; D002614:Chelating Agents; D004268:DNA-Binding Proteins; D008055:Lipids; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C070743:hupR1 protein, Rhodobacter capsulatus; C033223:polyhistidine; D006639:Histidine