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High-sensitivity detection of newly induced LamB protein on the Escherichia coli cell surface

Authors :
Vos-Scheperkeuter, G H
Hofnung, M
Witholt, B
Source :
Journal of Bacteriology; August 1984, Vol. 159 Issue: 2 p435-439, 5p
Publication Year :
1984

Abstract

The kinetics of the appearance at the cell surface of the outer membrane LamB protein after induction were determined by using specific antibodies and radioiodinated protein A as a probe. This was done in two different induction systems. First, LamB protein was induced in a wild-type strain by the simultaneous addition of cyclic AMP and maltose. Second, an operon fusion strain in which the lamB gene is expressed under lac promoter control was used; in this system, LamB protein can be induced by isopropyl-beta-D-thiogalactopyranoside. When uninduced cells were grown in glucose minimal medium, background expression of the lamB gene was found to be ca. 10-fold lower in lac-lamB cells than in wild-type cells. The level of LamB protein present in uninduced wild-type cells could, however, be reduced by supplementing the growth medium with Casamino Acids. After induction, the LamB protein appeared at the cell surface of both strains within a few minutes, and then the LamB level per cell increased linearly. The time lag in cell surface exposure of LamB protein differed slightly under both induction conditions: the LamB protein appeared at the surface of lac-lamB cells within 3 min of induction, whereas in wild-type cells it could not be detected earlier than after 4 to 5 min of induction.

Details

Language :
English
ISSN :
00219193 and 10985530
Volume :
159
Issue :
2
Database :
Supplemental Index
Journal :
Journal of Bacteriology
Publication Type :
Periodical
Accession number :
ejs57609273
Full Text :
https://doi.org/10.1128/jb.159.2.435-439.1984