title: Membrane targeting of a folded and cofactor-containing protein.
abstract: Targeting of proteins to and translocation across the membranes is a fundamental biological process in all organisms. In bacteria, the twin arginine translocation (Tat) system can transport folded proteins. Here, we demonstrate in vivo that the high potential iron-sulfur protein (HiPIP) from Allochromatium vinosum is translocated into the periplasmic space by the Tat system of Escherichia coli. In vitro, reconstituted HiPIP precursor (preHoloHiPIP) was targeted to inverted membrane vesicles from E. coli by a process requiring ATP when the Tat substrate was properly folded. During membrane targeting, the protein retained its cofactor, indicating that it was targeted in a folded state. Membrane targeting did not require a twin arginine motif and known Tat system components. On the basis of these findings, we propose that a pathway exists for the insertion of folded cofactor-containing proteins such as HiPIP into the bacterial cytoplasmic membrane.
authors.affiliation: Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA. t.brueser@mikrobiologie.uni-halle.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüser
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yano
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Brune
authors.forename: Fevzi
authors.initials: F
authors.lastname: Daldal
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism; D021382:Protein Sorting Signals; D021381:Protein Transport
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins; D026901:Membrane Transport Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; C007943:high potential iron-sulfur protein; C408585:twin-arginine translocase complex, E coli