title: SurA is involved in the targeting to the outer membrane of a Tat signal sequence-anchored protein.
abstract: The twin arginine translocation (Tat) pathway exports folded proteins from the cytoplasm to the periplasm of bacteria. The targeting of the exported proteins to the Tat pathway relies on a specific amino-terminal signal sequence, which is cleaved after exportation. In the phytopathogen Dickeya dadantii, the pectin lyase homologue PnlH is exported by the Tat pathway without cleavage of its signal sequence, which anchors PnlH into the outer membrane. In proteobacteria, the vast majority of outer membrane proteins consists of β-barrel proteins and lipoproteins. Thus, PnlH represents a new kind of outer membrane protein. In Escherichia coli, periplasmic chaperones SurA, Skp, and DegP work together with the β-barrel assembly machinery (Bam) to target and insert β-barrel proteins into the outer membrane. In this work, we showed that SurA is required for an efficient targeting of PnlH to the outer membrane. Moreover, we were able to detect an in vitro interaction between SurA and the PnlH signal sequence. Since the PnlH signal sequence contains a highly hydrophobic region, we propose that SurA protects it from the hydrophobic periplasm during targeting of PnlH to the outer membrane. We also studied the nature of the information carried by the PnlH signal sequence responsible for its targeting to the outer membrane after exportation by the Tat system.
authors.affiliation: Université de Lyon, F69003, Université Lyon 1, F69622, INSA-Lyon F69621, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Rondelet
authors.forename: Guy
authors.initials: G
authors.lastname: Condemine
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D020563:Gammaproteobacteria / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D011487:Protein Conformation; D021382:Protein Sorting Signals / Q000502:physiology*; D021381:Protein Transport; D012293:Rifampin / Q000494:pharmacology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D001616:beta-Galactosidase
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D015696:Gene Products, tat; D021382:Protein Sorting Signals; D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid; D001616:beta-Galactosidase; C490900:SurA protein, E coli; D019696:Peptidylprolyl Isomerase; D012293:Rifampin