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Updated: Jul 15, 2025

Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains
Published on: January 18, 2014
The Bacteroidetes Q-rule and glutaminyl cyclase activity increase the stability of extracytoplasmic proteins
Katarzyna Szczęśniak1, Florian Veillard1, Carsten Scavenius2
1Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University , Kraków, Poland.
Importance:
Exclusively in the Bacteroidetes phylum, most proteins exported across the inner membrane via the Sec system and released into the periplasm by type I signal peptidase have N-terminal glutamine converted to pyroglutamate. The reaction is catalyzed by the periplasmic enzyme glutaminyl cyclase (QC), which is essential for the growth of Porphyromonas gingivalis and other periodontopathogens. Apparently, pyroglutamyl formation stabilizes extracytoplasmic proteins and/or protects them from proteolytic degradation in the periplasm. Given the role of P. gingivalis as the keystone pathogen in periodontitis, P. gingivalis QC is a promising target for the development of drugs to treat and/or prevent this highly prevalent chronic inflammatory disease leading to tooth loss and associated with severe systemic diseases.
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