Team:Baskent Meds/Description

Project Descripton

Recognition of population density in environment by bacteria is possible by sensation of species specific signaling molecules. With quorum sensing (QS), via gene expression; symbiosis, virulence, antibiotic production and biofilm formation can be controlled at population level. In L. pneumophila, lqs (legionella quorum sensing) gene locus, which is composed of lqsA (autoinducer synthase), lqsR (response regulator) and lqsS (sensor kinase) genes, is responsible for this mechanism. lqsS, which recognizes Legionella presence due to lqsA secretion to environment, affects cellular metabolism by phosphorylation of lqsR. In order to make the lqs system more active, phosphorylated lqsR enhances its transcription by attaching its own promoter.
Our product is composed of 3 stages that are called “cassette”. In first cassette; lqsS and lqsR system elements are synthesized with constitutive promoter. While generating recombinant bacteria, lqsA is removed from gene cluster, otherwise the system would activate itself.

In second cassette; anti-legionella (Warnericin RK) peptide, which is directed to periplasmic space by pelB leader sequence, and some proteins are transcribed with lqsR promoter. The pelB leader sequence is a sequence of amino acids which when attached to a protein, directs the protein to the bacterial periplasm. lqsR promoter is activated by phosphorylated lqsR. This provides synthesis of anti-legionella (Warnericin RK) peptide and marker protein in case of lqsA presence in environment.

Third cassette contains febA L8T protein which is responsible from diffusion of synthesized proteins through cell membrane to outside of cell. It is transcribed with constitutive promoter. By this means, diffusion of proteins which are in periplasmic space is provided by generating pores on the outer membrane of the double layered membrane structure. Anti-legionella peptide, directed to periplasmic space, is secreted from cell in this manner.

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