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Home    Δομικός και φυσικοχημικός χαρακτηρισμός της πρωτεϊνης HrpA του βακτηρίου Pseudomonas syringae pv. phaseolicola του εκκριτικού συστήματος τύπου ΙΙΙ  

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Identifier 000370067
Title Δομικός και φυσικοχημικός χαρακτηρισμός της πρωτεϊνης HrpA του βακτηρίου Pseudomonas syringae pv. phaseolicola του εκκριτικού συστήματος τύπου ΙΙΙ
Alternative Title Structural and physicochemical characterization of the type III secretion system protein HrpA of Pseudomonas syringae pv. phaseolicola
Author Κοτζαμπασάκη, Μαριάννα Ιω.
Thesis advisor Κοκκινίδης, Μιχαήλ
Μητράκη, Αννα
Abstract Type III secretion systems (T3SSs) are needle-like structures used by Gram negative bacteria to translocate bacterial proteins (effectors) into eukaryotic cells. The T3SS pathway of plant pathogens is encoded by hrp (HR and pathogenicity) and hrc (HR and conserved) genes. The structural study of the HrpA protein, a small hydrophilic protein of the T3SS of P. syringae pv. phaseolicola will be presented. HrpA is the major component of T3SS pilus, a needle-like structure, whose diameter is about 6-8 nm and its length up to 2 μm. Recombinant wild type HrpA was overexpressed and purified by affinity chromatography. Moreover, physicochemical and structural study of HrpA protein was performed under different parameters (pH, concentration, shelf-life and temperature) with CD, FTIR, Raman spectroscopy and high resolution TEM. In addition, physicochemical and structural characterization of deletion mutant (HrpAΔC8) also took place under various conditions with affinity chromatography, CD, SAXS and high resolution TEM. Finally, the pilus of P. syringae pv. phaseolicola was purified in order to study its structural properties with HRTEM and to compare them with those of polymerized recombinant HrpA which forms fibre-like structures with nano- to micron scale features. According to the HRTEM observations, the in vitro formed fibers strongly resemble the structural parameters of Τ3SS pilus. Whereas HrpA is predicted to be a highly α-helical protein, its CD spectra indicate very low α-helical content and strongly resemble those of disordered proteins. Raman spectroscopy, FTIR and SAXS also support the CD observations.
Language English, Greek
Subject HRP pilus
HRTEM
T3SS
Issue date 2011-07-19
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
  Type of Work--Post-graduate theses
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