Home Life Sciences Ligand-Mediated Protection against Phage Lysis as a Positive Selection Strategy for the Enrichment of Epitopes Displayed on the Surface of E. coli Cells
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Ligand-Mediated Protection against Phage Lysis as a Positive Selection Strategy for the Enrichment of Epitopes Displayed on the Surface of E. coli Cells

  • Peter Camaj , Aaron E. Hirsh , Walter Schmidt , Andreas Meinke and Alexander von Gabain
Published/Copyright: June 1, 2005
Biological Chemistry
From the journal Volume 382 Issue 12

Abstract

We present a novel strategy, termed CISTEM, which allows direct in vivo screening of polypeptides displayed on the surface of E. coli cells by a combination of ligandmediated protection and phagemediated selection. The effectiveness of this new approach was demonstrated by displaying the T7tag on the surface of E. coli as a fusion with the outer membrane protein A, the receptor for bacteriophage K3. A monoclonal T7tag antibody was used as protective ligand for T7tagdisplaying cells and phage K3 for the elimination of unprotected cells. When populations of bacteria, containing between 6 to 10 000 cells displaying the T7tag and approximately 10exp8 cells displaying an unrelated OmpA fusion protein, were infected with phage K3, specific and antibodydependent survival of T7tag displaying cells was observed, yielding an enrichment factor of up to 10exp7-fold. The CISTEM technology was used to select sequences from a T7tagbased, randomised library and the results were compared to those obtained from selection by MACS with the same library. Together, these results reveal a novel in vivo screening strategy in which an E. coli phage receptor is used as display platform and selection is performed in suspension upon addition of a protective ligand and a bacteriophage. Extentions and modifications of the basic strategy should lead to novel applications for the identification of proteinligand interactions.

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Published Online: 2005-06-01
Published in Print: 2001-12-19

Copyright © 2001 by Walter de Gruyter GmbH & Co. KG

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