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Characterization of CetA and CetB, a bipartite energy taxis system in Campylobacter jejuni.

Elliott KT, Dirita VJ - Mol. Microbiol. (2008)

Bottom Line: The PAS domain (a sensory domain named after three proteins Per, ARNT and Sim, where it was first identified) is thought to interact directly with the Aer HAMP domain to transmit this signal to the highly conserved domain (HCD) found in chemotaxis receptors.CetA has two transmembrane helices in a helical hairpin while CetB is a peripheral membrane protein tightly associated with the membrane.This study provides a foundation for further characterization of signal transduction mechanisms within CetA/CetB.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA.

ABSTRACT
The energy taxis receptor Aer, in Escherichia coli, senses changes in the redox state of the electron transport system via an flavin adenine dinucleotide cofactor bound to a PAS domain. The PAS domain (a sensory domain named after three proteins Per, ARNT and Sim, where it was first identified) is thought to interact directly with the Aer HAMP domain to transmit this signal to the highly conserved domain (HCD) found in chemotaxis receptors. An apparent energy taxis system in Campylobacter jejuni is composed of two proteins, CetA and CetB, that have the domains of Aer divided between them. CetB has a PAS domain, while CetA has a predicted transmembrane region, HAMP domain and the HCD. In this study, we examined the expression of cetA and cetB and the biochemical properties of the proteins they encode. cetA and cetB are co-transcribed independently of the flagellar regulon. CetA has two transmembrane helices in a helical hairpin while CetB is a peripheral membrane protein tightly associated with the membrane. CetB levels are CetA dependent. Additionally, we demonstrated that both CetA and CetB participate in complexes, including a likely CetB dimer and a complex that may include both CetA and CetB. This study provides a foundation for further characterization of signal transduction mechanisms within CetA/CetB.

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Prediction of transmembrane regions for CetA and CetB.A. DAS analysis results for CetA.B. DAS analysis results for CetB.C. Hydrophobicity (Kyte–Doolittle values) of each residue within the DAS-predicted transmembrane region of CetA. Arrow indicates position of His-24.
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fig03: Prediction of transmembrane regions for CetA and CetB.A. DAS analysis results for CetA.B. DAS analysis results for CetB.C. Hydrophobicity (Kyte–Doolittle values) of each residue within the DAS-predicted transmembrane region of CetA. Arrow indicates position of His-24.

Mentions: We used the DAS (dense alignment surface) algorithm (Cserzo et al., 1997) to predict whether CetA and/or CetB possess transmembrane domains. According to this analysis, CetA has a transmembrane region of 36–38 amino acids in length from residues 6–43 or 7–42, depending on the cut-off used (Fig. 3A).


Characterization of CetA and CetB, a bipartite energy taxis system in Campylobacter jejuni.

Elliott KT, Dirita VJ - Mol. Microbiol. (2008)

Prediction of transmembrane regions for CetA and CetB.A. DAS analysis results for CetA.B. DAS analysis results for CetB.C. Hydrophobicity (Kyte–Doolittle values) of each residue within the DAS-predicted transmembrane region of CetA. Arrow indicates position of His-24.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2628428&req=5

fig03: Prediction of transmembrane regions for CetA and CetB.A. DAS analysis results for CetA.B. DAS analysis results for CetB.C. Hydrophobicity (Kyte–Doolittle values) of each residue within the DAS-predicted transmembrane region of CetA. Arrow indicates position of His-24.
Mentions: We used the DAS (dense alignment surface) algorithm (Cserzo et al., 1997) to predict whether CetA and/or CetB possess transmembrane domains. According to this analysis, CetA has a transmembrane region of 36–38 amino acids in length from residues 6–43 or 7–42, depending on the cut-off used (Fig. 3A).

Bottom Line: The PAS domain (a sensory domain named after three proteins Per, ARNT and Sim, where it was first identified) is thought to interact directly with the Aer HAMP domain to transmit this signal to the highly conserved domain (HCD) found in chemotaxis receptors.CetA has two transmembrane helices in a helical hairpin while CetB is a peripheral membrane protein tightly associated with the membrane.This study provides a foundation for further characterization of signal transduction mechanisms within CetA/CetB.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109, USA.

ABSTRACT
The energy taxis receptor Aer, in Escherichia coli, senses changes in the redox state of the electron transport system via an flavin adenine dinucleotide cofactor bound to a PAS domain. The PAS domain (a sensory domain named after three proteins Per, ARNT and Sim, where it was first identified) is thought to interact directly with the Aer HAMP domain to transmit this signal to the highly conserved domain (HCD) found in chemotaxis receptors. An apparent energy taxis system in Campylobacter jejuni is composed of two proteins, CetA and CetB, that have the domains of Aer divided between them. CetB has a PAS domain, while CetA has a predicted transmembrane region, HAMP domain and the HCD. In this study, we examined the expression of cetA and cetB and the biochemical properties of the proteins they encode. cetA and cetB are co-transcribed independently of the flagellar regulon. CetA has two transmembrane helices in a helical hairpin while CetB is a peripheral membrane protein tightly associated with the membrane. CetB levels are CetA dependent. Additionally, we demonstrated that both CetA and CetB participate in complexes, including a likely CetB dimer and a complex that may include both CetA and CetB. This study provides a foundation for further characterization of signal transduction mechanisms within CetA/CetB.

Show MeSH
Related in: MedlinePlus