| Abstract |
The type III secretion system (TTSS) is a multiprotein compex which functions as a protein transfer device that a) is capable of injecting structurally diverse protein substrates across the two bacterial and the eucaryotic cell membrane direcrtly into the eucaryotic cytosol, b) is triggered when the pathogen comes in close contact with host cells and c) also functions in vitro under appropriate conditions that mimic key parameteters of the host environment. Through this system, various effector proteins are secreted and translocated into the host cell to alter host cellular processes and either promote disease development or trigger host defense responses. The type III secretion system bears a structural core, which is well conserved among bacterial pathogens of mammals and plants. The present study concerns the characterization of the C-terminal soluble fragment of Pseudomonas syringae pv. Phaseolocola of the TTSS structural protein HrcU (HrcU C199) and also the potential interaction between this fragment and Q a) the Psph TTSS ATPase HrcN, b) the N terminal fragment of the Psph TTSS ATPase HrcN HrcN N261), c) the C terminal fragment of the Psph TTSS ATPase HrcN (HrcN C259), d) the Psph TTSS protein HrpP and also between the fragment HrcN C259 and the proteins AvrPhF-ORF1 and AvrPphF-ORF2 alone or as a compex. The fragment HrcU C199 is possibly cleaved at the well-conseeved pattern of proteolysis NPTH of the HrcU homologues (FlhB/YscU/HrcU/SpaS protein family) and the two proteolytic fragments seem to interact since they co-purify in affinity chromatography experiments. The methods used to identify the possible protein interactions that are stated above were mainly co-purification experiments and overlay procedures. These methods indetified to interaction concerning the protein pairs examined.
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Καθαρισμός και μελέτη αλληλεπιδράσεων μεταξύ πρωτεϊνών που δομούν το εκκριτικό σύστημα τύπου ΙΙΙ σε παθογόνα βακτήρια
