title: Structures of the signal recognition particle receptor from the archaeon Pyrococcus furiosus: implications for the targeting step at the membrane.
abstract: In all organisms, a ribonucleoprotein called the signal recognition particle (SRP) and its receptor (SR) target nascent proteins from the ribosome to the translocon for secretion or membrane insertion. We present the first X-ray structures of an archeal FtsY, the receptor from the hyper-thermophile Pyrococcus furiosus (Pfu), in its free and GDP*magnesium-bound forms. The highly charged N-terminal domain of Pfu-FtsY is distinguished by a long N-terminal helix. The basic charges on the surface of this helix are likely to regulate interactions at the membrane. A peripheral GDP bound near a regulatory motif could indicate a site of interaction between the receptor and ribosomal or SRP RNAs. Small angle X-ray scattering and analytical ultracentrifugation indicate that the crystal structure of Pfu-FtsY correlates well with the average conformation in solution. Based on previous structures of two sub-complexes, we propose a model of the core of archeal and eukaryotic SRP*SR targeting complexes.
authors.affiliation: Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA. pascal@msg.ucsf.edu
authors.forename: Pascal F
authors.initials: PF
authors.lastname: Egea
authors.forename: Hiro
authors.initials: H
authors.lastname: Tsuruta
authors.forename: Gladys P
authors.initials: GP
authors.lastname: de Leon
authors.forename: Johanna
authors.initials: J
authors.lastname: Napetschnig
authors.forename: Peter
authors.initials: P
authors.lastname: Walter
authors.forename: Robert M
authors.initials: RM
authors.lastname: Stroud
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism*; D060365:Chloroplast Proteins; D018360:Crystallography, X-Ray; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry; D006153:Guanosine Diphosphate / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry; D008958:Models, Molecular; D011485:Protein Binding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D020027:Pyrococcus furiosus / Q000737:chemistry / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000378:metabolism*; D018000:Receptors, Peptide / Q000737:chemistry* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D008565:Membrane Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D018000:Receptors, Peptide; C513946:cpFtsY protein, Arabidopsis; C036318:signal peptide receptor; D006153:Guanosine Diphosphate; C072146:Pfu DNA polymerase; D004259:DNA-Directed DNA Polymerase