title: Correlation between signal input and output in PctA and PctB amino acid chemoreceptor of Pseudomonas aeruginosa.
abstract: The PctA and PctB chemoreceptors of Pseudomonas aeruginosa mediate chemotaxis toward amino acids. A general feature of signal transduction processes is that a signal input is converted into an output. We have generated chimeras combining the Tar signaling domain with either the PctA or PctB ligand binding domain (LBD). Escherichia coli harboring either PctA-Tar or PctB-Tar mediated chemotaxis toward amino acids. The responses of both chimeras were determined using fluorescence resonance energy transfer, and the derived EC50 values are a measure of output. PctA-Tar and PctB-Tar responded to 19 and 11 L-amino acids respectively. The EC50 values of PctA-Tar responses differed by more than three orders of magnitude, whereas PctB-Tar responded preferentially to L-Gln. The comparison of amino acid binding constants and the corresponding EC50 values for both receptors revealed statistically significant correlations between inputs and outputs. PctA and PctB possess a double PDC (PhoQ-DcuS-CitA) LBD - a family of binding domain found in various other amino acid chemoreceptors. Similarly, various chemoreceptors share the preferential response to certain amino acids (e.g. L-Cys, L-Ser and L-Thr) that we observed for PctA. Defining the specific inputs and outputs of these chemoreceptors is an important step toward better understanding of their physiological role.
authors: Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/ Prof. Albareda, 1, Granada, 18008, Spain.
authors: José A
authors: JA
authors: Reyes-Darias
authors: Yiling
authors: Y
authors: Yang
authors: Victor
authors: V
authors: Sourjik
authors: Tino
authors: T
authors: Krell
mesh_terms: D020816:Amino Acid Motifs; D000596:Amino Acids / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002633:Chemotaxis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; C110124:PctA protein, Pseudomonas aeruginosa; C110122:PctB protein, Pseudomonas aeruginosa; D011994:Recombinant Proteins