title: The crystal structure of the signal recognition particle in complex with its receptor.
abstract: Cotranslational targeting of membrane and secretory proteins is mediated by the universally conserved signal recognition particle (SRP). Together with its receptor (SR), SRP mediates the guanine triphosphate (GTP)-dependent delivery of translating ribosomes bearing signal sequences to translocons on the target membrane. Here, we present the crystal structure of the SRP:SR complex at 3.9 angstrom resolution and biochemical data revealing that the activated SRP:SR guanine triphosphatase (GTPase) complex binds the distal end of the SRP hairpin RNA where GTP hydrolysis is stimulated. Combined with previous findings, these results suggest that the SRP:SR GTPase complex initially assembles at the tetraloop end of the SRP RNA and then relocalizes to the opposite end of the RNA. This rearrangement provides a mechanism for coupling GTP hydrolysis to the handover of cargo to the translocon.
authors.affiliation: Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zurich (ETH Zurich), Zurich, Switzerland.
authors.forename: Sandro F
authors.initials: SF
authors.lastname: Ataide
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Schmitz
authors.forename: Kuang
authors.initials: K
authors.lastname: Shen
authors.forename: Ailong
authors.initials: A
authors.lastname: Ke
authors.forename: Shu-ou
authors.initials: SO
authors.lastname: Shan
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Doudna
authors.forename: Nenad
authors.initials: N
authors.lastname: Ban
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008954:Models, Biological; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012329:RNA, Bacterial / Q000737:chemistry* / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D018271:Signal Recognition Particle / Q000737:chemistry* / Q000378:metabolism
chemical_list: C409968:4.5S RNA; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C082931:Ffh protein, E coli; C087406:FtsY protein, Bacteria; D012329:RNA, Bacterial; D018160:Receptors, Cytoplasmic and Nuclear; D012269:Ribosomal Proteins; D018271:Signal Recognition Particle; C043816:ribosomal protein L23, E coli; C035078:ribosomal protein L29; C004805:5'-guanylylmethylenebisphosphonate; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases