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Proceedings Paper

Structural basis of the Escherichi coli outer-membrane permeability
Author(s): Nabil A. Amro; Lakshmi P. Kotra; Kapila Wadu-Mesthrige; Alexy Bulychev; Shahriar Mobashery; Gang-yu Liu
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Paper Abstract

We have studied, using AFM, the structural basis of the outer membrane permeability for the bacterium E. col. The surface of the bacteria is visualized with an unprecedented details. Our AFM images clearly reveal that the outer membrane exhibits protrusions, which correspond to patches of LPS containing hundreds to thousands of LPS molecules. The packing of the nearest neighbor patches is tight, and as such the LPS layer provides an effective permeability barrier for the Gram-negative bacteria. We have also studied the mechanism of their permeability increase upon metal depletion. Our AFM images reveal that LPS molecules are released from the boundaries of some patches during the initial EDTA treatment. Further metal depletion produces a very distinct structure at the outer membrane: appearance of irregularly shaped pits. The pits are likely formed as a result of liberation of LPS patches and lipoproteins, exposing areas of peptidoglacan surface. Our study has proven AFM to be a very useful technique in providing structural basis for the functions of organisms.

Paper Details

Date Published: 17 June 1999
PDF: 15 pages
Proc. SPIE 3607, Scanning and Force Microscopies for Biomedical Applications, (17 June 1999); doi: 10.1117/12.350625
Show Author Affiliations
Nabil A. Amro, Wayne State Univ. (United States)
Lakshmi P. Kotra, Wayne State Univ. (United States)
Kapila Wadu-Mesthrige, Wayne State Univ. (United States)
Alexy Bulychev, Wayne State Univ. (United States)
Shahriar Mobashery, Wayne State Univ. (United States)
Gang-yu Liu, Wayne State Univ. (United States)

Published in SPIE Proceedings Vol. 3607:
Scanning and Force Microscopies for Biomedical Applications
Eiichi Tamiya; Shuming Nie, Editor(s)

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