Journal of Bioenergetics and Biomembranes

, Volume 22, Issue 3, pp 441–449

Export and sorting of theEscherichia coli outer membrane protein OmpA

  • Roland Freudl
  • Michael Klose
  • Ulf Henning
Mini-Review

DOI: 10.1007/BF00763176

Cite this article as:
Freudl, R., Klose, M. & Henning, U. J Bioenerg Biomembr (1990) 22: 441. doi:10.1007/BF00763176

Abstract

Results of studies, mostly using the outer membrane, 325 residue protein OmpA, are reviewed which concern its translocation across the plasma membrane and incorporation into the outer membrane ofEscherichia coli. For translocation, neither a unique export signal, acting in a positive fashion within the mature part of the precursor, nor a unique conformation of the precursor is required. Rather, the mature part of a secretory protein has to be export-compatible. Export-incompatibility can be caused by a stretch of 16 (but not 8 or 12) hydrophobic residues, too low a size of the polypeptide (smaller than 75 residue precursors), net positive charge at the N-terminus, or lack of a turn potential at the same site. It is not yet clear whether binding sites for chaperonins (SecB, trigger factor, GroEL) within OmpA are importantin vivo. The mechanism of sorting of outer membrane proteins is not yet understood. The membrane part of OmpA, encompassing residues 1 to about 170, it thought to traverse the membrane eight times in antiparallel β-sheet conformation. At least the structure of the last β-strand (residues 160–170) is of crucial importance for membrane assembly. It must be amphiphilic or hydrophobic, these properties must extend over at least nine residues, and it must not contain a proline residue at or near its center. Membrane incorporation of OmpA involves a conformational change of the protein and it could be that the last β-strand initiates folding and assembly in the outer membrane.

Key Words

Escherichia coli plasma membrane outer membrane OmpA protein translocation/sorting 

Copyright information

© Plenum Publishing Corporation 1990

Authors and Affiliations

  • Roland Freudl
    • 1
  • Michael Klose
    • 2
  • Ulf Henning
    • 2
  1. 1.Institut für Biotechnologie der Kernforschungsanlage JülichJülichGermany
  2. 2.Max-Planck-Institut für BiologieTübingenGermany

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