title: Structural studies on a twin-arginine signal sequence.
abstract: Translocation of folded proteins across biological membranes can be mediated by the so-called 'twin-arginine translocation' (Tat) system. To be translocated, Tat substrates require N-terminal signal sequences which usually contain the eponymous twin-arginine motif. Here we report the first structural analysis of a twin-arginine signal sequence, the signal sequence of the high potential iron-sulfur protein from Allochromatium vinosum. Nuclear magnetic resonance (NMR) analyses of amide proton resonances did not indicate a signal sequence structure. Accordingly, data from H/D exchange matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry showed that the amide protons of the signal sequence exchange rapidly, indicating the absence of secondary structure in the signal sequence up to L29. We conclude that the conserved twin-arginine motif does not form a structure by itself or as a result of intramolecular interactions.
authors.affiliation: Max Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, D-06120 Halle, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Kipping
authors.forename: Hauke
authors.initials: H
authors.lastname: Lilie
authors.forename: Ute
authors.initials: U
authors.lastname: Lindenstrauss
authors.forename: Jan R
authors.initials: JR
authors.lastname: Andreesen
authors.forename: Christian
authors.initials: C
authors.lastname: Griesinger
authors.forename: Teresa
authors.initials: T
authors.lastname: Carlomagno
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüser
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002841:Chromatiaceae / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D021382:Protein Sorting Signals; D021381:Protein Transport; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D004151:Dipeptides; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D021382:Protein Sorting Signals; C007943:high potential iron-sulfur protein; C076685:arginylarginine; D006859:Hydrogen