Topological and deletion analysis of CorS, a Pseudomonas syringae sensor kinase.
A modified two-component regulatory system consisting of two response regulators, CorR and CorP, and the histidine protein kinase CorS, regulates the thermoresponsive production of the phytotoxin coronatine (COR) in Pseudomonas syringae PG4180. COR is produced at the virulence-promoting temperature of 18 degrees C, but not at 28 degrees C, the optimal growth temperature of PG4180. Assuming that the highly hydrophobic N-terminus of CorS might be involved in temperature-signal perception, the membrane topology of CorS was determined using translational phoA and lacZ fusions, leading to a topological model for CorS with six transmembrane domains (TMDs). Interestingly, three PhoA fusions located downstream of the sixth TMD showed a thermoresponsive phenotype. Enzymic activity, immunoblot, and protease-sensitivity assays were performed to localize the CorS derivatives, to analyse the expression level of hybrid proteins and to examine the model. In-frame deletions of the last four, or all six TMDs gave rise to non-functional CorS. The results indicated that the transmembrane region is important for CorS to function as a temperature sensor, and that the membrane topology of CorS might be involved in signal perception.
International University Bremen, School of Engineering and Sciences, Research II, Campus Ring 1, 28759 Bremen, Germany.
Angela V
AV
Smirnova
International University Bremen, School of Engineering and Sciences, Research II, Campus Ring 1, 28759 Bremen, Germany.
Matthias S
MS
Ullrich
D000469:Alkaline Phosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D000071677:Histidine Kinase; D007763:Lac Operon; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010641:Phenotype; D011494:Protein Kinases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D044224:Pseudomonas syringae / Q000201:enzymology* / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D013696:Temperature
D001426:Bacterial Proteins; C096448:CorS protein, Pseudomonas syringae; D004269:DNA, Bacterial; D011993:Recombinant Fusion Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; D000469:Alkaline Phosphatase