Discovery - University of Dundee - Online Publications

Library & Learning Centre

Escherichia coli TatA and TatB Proteins Have N-out, C-in Topology in Intact Cells

Escherichia coli TatA and TatB Proteins Have N-out, C-in Topology in Intact Cells

Research output: Contribution to journalArticle

View graph of relations

Authors

  • Sabrina Koch
  • Maximilian J. Fritsch
  • Grant Buchanan
  • Tracy Palmer (Lead / Corresponding author)

Research units

Info

Original languageEnglish
Pages14420-14431
Number of pages12
JournalJournal of Biological Chemistry
Journal publication date27 Apr 2012
Journal number18
Volume287
DOIs
StatePublished

Abstract

The twin arginine protein transport (Tat) system translocates folded proteins across the cytoplasmic membrane of pro-karyotes and the thylakoid membrane of chloroplasts. In Escherichia coli, TatA, TatB, and TatC are essential components of the machinery. Acomplex of TatB and TatC acts as the substrate receptor, whereas TatA is proposed to form the Tat transport channel. TatA and TatB are related proteins that comprise an N-terminal transmembrane helix and an adjacent amphipathic helix. Previous studies addressing the topological organization of TatA have given conflicting results. In this study, we have addressed the topological arrangement of TatA and TatB in intact cells by labeling of engineered cysteine residues with the membrane-impermeable thiol reagent methoxypolyethylene glycol maleimide. Our results show that TatA and TatB share an N-out, C-in topology, with no evidence that the amphipathic helices of either protein are exposed at the periplasmic side of the membrane. We further show that the N-out, C-in topology of TatA is fixed and is not affected by the absence of other Tat components or by the overproduction of a Tat substrate. These data indicate that topological reorganization of TatA is unlikely to accompany Tat-dependent protein transport.

Download statistics

No data available

Documents

Documents

DOI

Library & Learning Centre

Contact | Accessibility | Policy