1. Precise localization of an overproduced periplasmic protein in Escherichia coli: use of double immuno-gold labelling
- Author
-
Alain Bernadac, Jean Michel Bolla, M. Inouye, C. Lazdunski, and J. M. Pages
- Subjects
Immunoassay ,Antiserum ,Immune Sera ,Vesicle ,Genetic Vectors ,Cell Biology ,General Medicine ,Periplasmic space ,Biology ,medicine.disease_cause ,Subcellular localization ,beta-Lactamases ,Microscopy, Electron ,Biochemistry ,Cytoplasm ,Escherichia coli ,medicine ,Gold ,Overproduction ,Bacterial outer membrane ,Plasmids - Abstract
The subcellular localization of beta-lactamase produced by a secretion-cloning vector pIN-III was studied by immunolabelling of frozen thin sections of Escherichia coli. Using double immuno-gold detections and internal reference proteins, it is shown here that beta-lactamase encoded by this vector can be exported and that its overproduction leads to aggregation within the periplasm. This aggregation induces the appearance of electron-dense areas immunolabelled by the antiserum directed against the beta-lactamase at the external side of the cytoplasmic membrane. The overproduced enzyme is also secreted to the medium in vesicles budding from the outer membrane of lpp strains.
- Published
- 1987